diff --git a/.Rbuildignore b/.Rbuildignore
index 2351955..0e0e531 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -12,3 +12,6 @@ src/vendor/*
 ^CRAN-SUBMISSION$
 ^src/rust/vendor$
 ^src/rust/vendor-authors.R$
+^src/rust/target$
+^src/Makevars$
+^src/Makevars\.win$
diff --git a/.gitignore b/.gitignore
index ba1e91c..5661812 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
 .Rproj.user
 docs
 src/rust/vendor
+src/Makevars
+src/Makevars.win
diff --git a/DESCRIPTION b/DESCRIPTION
index 2f26f03..1507df8 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: rtiktoken
 Title: A Byte-Pair-Encoding (BPE) Tokenizer for OpenAI's Large Language Models
-Version: 0.0.6
+Version: 0.0.7
 Authors@R: c(
     person("David", "Zimmermann-Kollenda", , "david_j_zimmermann@hotmail.com", role = c("aut", "cre")),
     person("Roger Zurawicki", role = "aut", comment = "tiktoken-rs Rust library"),
@@ -16,6 +16,8 @@ SystemRequirements: Cargo (Rust's package manager), rustc >= 1.65.0
 Encoding: UTF-8
 Roxygen: list(markdown = TRUE)
 RoxygenNote: 7.3.2
-Config/rextendr/version: 0.3.1
+Config/rextendr/version: 0.3.1.9001
 Config/testthat/edition: 3
 Config/rtiktoken/MSRV: 1.65.0
+Depends: 
+    R (>= 4.2)
diff --git a/NEWS.md b/NEWS.md
index 27c1983..92db071 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,15 +1,19 @@
-# rtiktoken 0.5
-
-* switch to rextendr defaults for configure and makevars
-
-# rtiktoken 0.3, 0.4
-
-* fix build for CRAN
-
-# rtiktoken 0.2
-
-* fix Notes and Warning for CRAN release
-
-# rtiktoken 0.1
-
-* Initial functionality & tests
+# rtiktoken 0.0.7
+
+* update extendr version and templates to address non API changes and symbols testing in R 4.5
+
+# rtiktoken 0.5
+
+* switch to rextendr defaults for configure and makevars
+
+# rtiktoken 0.3, 0.4
+
+* fix build for CRAN
+
+# rtiktoken 0.2
+
+* fix Notes and Warning for CRAN release
+
+# rtiktoken 0.1
+
+* Initial functionality & tests
diff --git a/configure b/configure
old mode 100644
new mode 100755
index 0f4c1be..c608b11
--- a/configure
+++ b/configure
@@ -1,3 +1,3 @@
 #!/usr/bin/env sh
 : "${R_HOME=`R RHOME`}"
-"${R_HOME}/bin/Rscript" tools/msrv.R 
+"${R_HOME}/bin/Rscript" tools/config.R 
diff --git a/configure.win b/configure.win
index f1945ac..57eb255 100644
--- a/configure.win
+++ b/configure.win
@@ -1,2 +1,2 @@
 #!/usr/bin/env sh
-"${R_HOME}/bin${R_ARCH_BIN}/Rscript.exe" tools/msrv.R
+"${R_HOME}/bin${R_ARCH_BIN}/Rscript.exe" tools/config.R
diff --git a/src/Makevars b/src/Makevars
deleted file mode 100644
index 2806c58..0000000
--- a/src/Makevars
+++ /dev/null
@@ -1,36 +0,0 @@
-TARGET_DIR = ./rust/target
-LIBDIR = $(TARGET_DIR)/release
-STATLIB = $(LIBDIR)/librtiktoken.a
-PKG_LIBS = -L$(LIBDIR) -lrtiktoken
-
-all: C_clean
-
-$(SHLIB): $(STATLIB)
-
-CRAN_FLAGS=-j 2 --offline
-CARGOTMP = $(CURDIR)/.cargo
-VENDOR_DIR = $(CURDIR)/vendor
-
-$(STATLIB):
-	if [ -f ./rust/vendor.tar.xz ]; then \
-		tar xf rust/vendor.tar.xz && \
-		mkdir -p $(CARGOTMP) && \
-		cp rust/vendor-config.toml $(CARGOTMP)/config.toml; \
-	fi
-
-	# In some environments, ~/.cargo/bin might not be included in PATH, so we need
-	# to set it here to ensure cargo can be invoked. It is appended to PATH and
-	# therefore is only used if cargo is absent from the user's PATH.
-	if [ "$(NOT_CRAN)" != "true" ]; then \
-		export CARGO_HOME=$(CARGOTMP); \
-	fi && \
-		export PATH="$(PATH):$(HOME)/.cargo/bin" && \
-			cargo build $(CRAN_FLAGS) --lib --release --manifest-path=./rust/Cargo.toml --target-dir $(TARGET_DIR) && \
-			echo `cargo --version` && echo `rustc --version`;
-		rm -Rf $(CARGOTMP) $(VENDOR_DIR) $(LIBDIR)/build; \
-
-C_clean:
-	rm -Rf $(SHLIB) $(STATLIB) $(OBJECTS) $(CARGOTMP) $(VENDOR_DIR)
-
-clean:
-	rm -Rf $(SHLIB) $(STATLIB) $(OBJECTS) $(CARGOTMP) $(VENDOR_DIR) $(TARGET_DIR)
diff --git a/src/Makevars.in b/src/Makevars.in
new file mode 100644
index 0000000..0560a1c
--- /dev/null
+++ b/src/Makevars.in
@@ -0,0 +1,46 @@
+TARGET_DIR = ./rust/target
+LIBDIR = $(TARGET_DIR)/@LIBDIR@
+STATLIB = $(LIBDIR)/librtiktoken.a
+PKG_LIBS = -L$(LIBDIR) -lrtiktoken
+
+all: $(SHLIB) rust_clean
+
+.PHONY: $(STATLIB)
+
+$(SHLIB): $(STATLIB)
+
+CARGOTMP = $(CURDIR)/.cargo
+VENDOR_DIR = $(CURDIR)/vendor
+
+
+# RUSTFLAGS appends --print=native-static-libs to ensure that 
+# the correct linkers are used. Use this for debugging if need. 
+#
+# CRAN note: Cargo and Rustc versions are reported during
+# configure via tools/msrv.R.
+#
+# When the NOT_CRAN flag is *not* set, the vendor.tar.xz, if present,
+# is unzipped and used for offline compilation.
+$(STATLIB):
+
+	# Check if NOT_CRAN is false and unzip vendor.tar.xz if so
+	if [ "$(NOT_CRAN)" != "true" ]; then \
+		if [ -f ./rust/vendor.tar.xz ]; then \
+			tar xf rust/vendor.tar.xz && \
+			mkdir -p $(CARGOTMP) && \
+			cp rust/vendor-config.toml $(CARGOTMP)/config.toml; \
+		fi; \
+	fi
+
+	export CARGO_HOME=$(CARGOTMP) && \
+	export PATH="$(PATH):$(HOME)/.cargo/bin" && \
+	RUSTFLAGS="$(RUSTFLAGS) --print=native-static-libs" cargo build @CRAN_FLAGS@ --lib @PROFILE@ --manifest-path=./rust/Cargo.toml --target-dir $(TARGET_DIR)
+
+	# Always clean up CARGOTMP
+	rm -Rf $(CARGOTMP);
+
+rust_clean: $(SHLIB)
+	rm -Rf $(CARGOTMP) $(VENDOR_DIR) @CLEAN_TARGET@
+
+clean:
+	rm -Rf $(SHLIB) $(STATLIB) $(OBJECTS) $(TARGET_DIR)
diff --git a/src/Makevars.ucrt b/src/Makevars.ucrt
deleted file mode 100644
index 17b153e..0000000
--- a/src/Makevars.ucrt
+++ /dev/null
@@ -1,5 +0,0 @@
-# Rtools42 doesn't have the linker in the location that cargo expects, so we
-# need to overwrite it via configuration.
-CARGO_LINKER = x86_64-w64-mingw32.static.posix-gcc.exe
-
-include Makevars.win
diff --git a/src/Makevars.win b/src/Makevars.win
deleted file mode 100644
index 3350e2c..0000000
--- a/src/Makevars.win
+++ /dev/null
@@ -1,48 +0,0 @@
-TARGET = $(subst 64,x86_64,$(subst 32,i686,$(WIN)))-pc-windows-gnu
-
-TARGET_DIR = ./rust/target
-LIBDIR = $(TARGET_DIR)/$(TARGET)/release
-STATLIB = $(LIBDIR)/librtiktoken.a
-PKG_LIBS = -L$(LIBDIR) -lrtiktoken -lws2_32 -ladvapi32 -luserenv -lbcrypt -lntdll
-
-all: C_clean
-
-$(SHLIB): $(STATLIB)
-
-CRAN_FLAGS=-j 2 --offline
-CARGOTMP = $(CURDIR)/.cargo
-VENDOR_DIR = $(CURDIR)/vendor
-
-$(STATLIB):
-	# uncompress vendored deps
-	if [ -f ./rust/vendor.tar.xz ]; then \
-		tar xf rust/vendor.tar.xz && \
-		mkdir -p $(CARGOTMP) && \
-		cp rust/vendor-config.toml $(CARGOTMP)/config.toml; \
-	fi
-
-	mkdir -p $(TARGET_DIR)/libgcc_mock
-	# `rustc` adds `-lgcc_eh` flags to the compiler, but Rtools' GCC doesn't have
-	# `libgcc_eh` due to the compilation settings. So, in order to please the
-	# compiler, we need to add empty `libgcc_eh` to the library search paths.
-	# For more details, please refer to
-	# https://github.com/r-windows/rtools-packages/blob/2407b23f1e0925bbb20a4162c963600105236318/mingw-w64-gcc/PKGBUILD#L313-L316
-	touch $(TARGET_DIR)/libgcc_mock/libgcc_eh.a
-
-	# CARGO_LINKER is provided in Makevars.ucrt for R >= 4.2
-	if [ "$(NOT_CRAN)" != "true" ]; then \
-		export CARGO_HOME=$(CARGOTMP); \
-	fi && \
-		export CARGO_TARGET_X86_64_PC_WINDOWS_GNU_LINKER="$(CARGO_LINKER)" && \
-		export LIBRARY_PATH="$${LIBRARY_PATH};$(CURDIR)/$(TARGET_DIR)/libgcc_mock"; \
-		cargo build $(CRAN_FLAGS) --target=$(TARGET) --lib --release --manifest-path=./rust/Cargo.toml --target-dir $(TARGET_DIR) && \
-		echo `cargo --version` && echo `rustc --version`;
-	if [ "$(NOT_CRAN)" != "true" ]; then \
-		rm -Rf $(CARGOTMP) $(VENDOR_DIR) $(LIBDIR)/build; \
-	fi
-
-C_clean:
-	rm -Rf $(SHLIB) $(STATLIB) $(OBJECTS) $(CARGOTMP) $(VENDOR_DIR)
-
-clean:
-	rm -Rf $(SHLIB) $(STATLIB) $(OBJECTS) $(CARGOTMP) $(VENDOR_DIR) $(TARGET_DIR)
diff --git a/src/Makevars.win.in b/src/Makevars.win.in
new file mode 100644
index 0000000..e234a67
--- /dev/null
+++ b/src/Makevars.win.in
@@ -0,0 +1,41 @@
+TARGET = $(subst 64,x86_64,$(subst 32,i686,$(WIN)))-pc-windows-gnu
+
+TARGET_DIR = ./rust/target
+LIBDIR = $(TARGET_DIR)/$(TARGET)/@LIBDIR@
+STATLIB = $(LIBDIR)/librtiktoken.a
+PKG_LIBS = -L$(LIBDIR) -lrtiktoken -lws2_32 -ladvapi32 -luserenv -lbcrypt -lntdll
+
+all: $(SHLIB) rust_clean
+
+.PHONY: $(STATLIB)
+
+$(SHLIB): $(STATLIB)
+
+CARGOTMP = $(CURDIR)/.cargo
+VENDOR_DIR = vendor
+
+$(STATLIB):
+	mkdir -p $(TARGET_DIR)/libgcc_mock
+	touch $(TARGET_DIR)/libgcc_mock/libgcc_eh.a
+
+	if [ "$(NOT_CRAN)" != "true" ]; then \
+		if [ -f ./rust/vendor.tar.xz ]; then \
+			tar xf rust/vendor.tar.xz && \
+			mkdir -p $(CARGOTMP) && \
+			cp rust/vendor-config.toml $(CARGOTMP)/config.toml; \
+		fi; \
+	fi
+
+	# Build the project using Cargo with additional flags
+	export CARGO_HOME=$(CARGOTMP) && \
+	export LIBRARY_PATH="$(LIBRARY_PATH);$(CURDIR)/$(TARGET_DIR)/libgcc_mock" && \
+	RUSTFLAGS="$(RUSTFLAGS) --print=native-static-libs" cargo build @CRAN_FLAGS@ --target=$(TARGET) --lib @PROFILE@ --manifest-path=rust/Cargo.toml --target-dir=$(TARGET_DIR)
+
+	# Always clean up CARGOTMP
+	rm -Rf $(CARGOTMP);
+
+rust_clean: $(SHLIB)
+	rm -Rf $(CARGOTMP) $(VENDOR_DIR) @CLEAN_TARGET@
+
+clean:
+	rm -Rf $(SHLIB) $(STATLIB) $(OBJECTS) $(TARGET_DIR)
diff --git a/src/rust/Cargo.lock b/src/rust/Cargo.lock
index baa0619..0fc754a 100644
--- a/src/rust/Cargo.lock
+++ b/src/rust/Cargo.lock
@@ -13,9 +13,9 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.89"
+version = "1.0.97"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "86fdf8605db99b54d3cd748a44c6d04df638eb5dafb219b135d0149bd0db01f6"
+checksum = "dcfed56ad506cb2c684a14971b8861fdc3baaaae314b9e5f9bb532cbe3ba7a4f"
 
 [[package]]
 name = "autocfg"
@@ -46,21 +46,27 @@ checksum = "349f9b6a179ed607305526ca489b34ad0a41aed5f7980fa90eb03160b69598fb"
 
 [[package]]
 name = "bitflags"
-version = "2.6.0"
+version = "2.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b048fb63fd8b5923fc5aa7b340d8e156aec7ec02f0c78fa8a6ddc2613f6f71de"
+checksum = "5c8214115b7bf84099f1309324e63141d4c5d7cc26862f97a0a857dbefe165bd"
 
 [[package]]
 name = "bstr"
-version = "1.10.0"
+version = "1.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "40723b8fb387abc38f4f4a37c09073622e41dd12327033091ef8950659e6dc0c"
+checksum = "234113d19d0d7d613b40e86fb654acf958910802bcceab913a4f9e7cda03b1a4"
 dependencies = [
  "memchr",
  "regex-automata",
  "serde",
 ]
 
+[[package]]
+name = "build-print"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4a2128d00b7061b82b72844a351e80acd29e05afc60e9261e2ac90dca9ecc2ac"
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
@@ -69,21 +75,30 @@ checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
 [[package]]
 name = "extendr-api"
-version = "0.7.1"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "67505d96c7faa49d20e749dba7ba2447db52c40a788fd88cc2b6bef02c02277a"
+checksum = "cae12193370e4f00f4a54b64f40dabc753ad755f15229c367e4b5851ed206954"
 dependencies = [
+ "extendr-ffi",
  "extendr-macros",
- "libR-sys",
  "once_cell",
  "paste",
 ]
 
+[[package]]
+name = "extendr-ffi"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b48f96b7a4a2ff009ad9087f22a6de2312731a4096b520e3eb1c483df476ae95"
+dependencies = [
+ "build-print",
+]
+
 [[package]]
 name = "extendr-macros"
-version = "0.7.1"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "81b58838056f294411d0b2c35ac1a2b24c507d6828b75f2c1e74f00ee9b99267"
+checksum = "fdbbac9afddafddb4dabd10aefa8082e3f057ec5bfa519c7b44af114e7ebf1a5"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -106,17 +121,11 @@ version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
 
-[[package]]
-name = "libR-sys"
-version = "0.7.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "06ac9752bc1e83f5a354a62b9e81bd8db4468b1008e29f262441e7f0e91e6bb3"
-
 [[package]]
 name = "libc"
-version = "0.2.159"
+version = "0.2.171"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "561d97a539a36e26a9a5fad1ea11a3039a67714694aaa379433e580854bc3dc5"
+checksum = "c19937216e9d3aa9956d9bb8dfc0b0c8beb6058fc4f7a4dc4d850edf86a237d6"
 
 [[package]]
 name = "lock_api"
@@ -136,9 +145,9 @@ checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
 
 [[package]]
 name = "once_cell"
-version = "1.20.2"
+version = "1.21.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1261fe7e33c73b354eab43b1273a57c8f967d0391e80353e51f764ac02cf6775"
+checksum = "42f5e15c9953c5e4ccceeb2e7382a716482c34515315f7b03532b8b4e8393d2d"
 
 [[package]]
 name = "parking_lot"
@@ -171,36 +180,36 @@ checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.87"
+version = "1.0.94"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b3e4daa0dcf6feba26f985457cdf104d4b4256fc5a09547140f3631bb076b19a"
+checksum = "a31971752e70b8b2686d7e46ec17fb38dad4051d94024c88df49b667caea9c84"
 dependencies = [
  "unicode-ident",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.37"
+version = "1.0.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5b9d34b8991d19d98081b46eacdd8eb58c6f2b201139f7c5f643cc155a633af"
+checksum = "1885c039570dc00dcb4ff087a89e185fd56bae234ddc7f056a945bf36467248d"
 dependencies = [
  "proc-macro2",
 ]
 
 [[package]]
 name = "redox_syscall"
-version = "0.5.7"
+version = "0.5.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9b6dfecf2c74bce2466cabf93f6664d6998a69eb21e39f4207930065b27b771f"
+checksum = "d2f103c6d277498fbceb16e84d317e2a400f160f46904d5f5410848c829511a3"
 dependencies = [
  "bitflags",
 ]
 
 [[package]]
 name = "regex"
-version = "1.11.0"
+version = "1.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "38200e5ee88914975b69f657f0801b6f6dccafd44fd9326302a4aaeecfacb1d8"
+checksum = "b544ef1b4eac5dc2db33ea63606ae9ffcfac26c1416a2806ae0bf5f56b201191"
 dependencies = [
  "aho-corasick",
  "memchr",
@@ -210,9 +219,9 @@ dependencies = [
 
 [[package]]
 name = "regex-automata"
-version = "0.4.8"
+version = "0.4.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "368758f23274712b504848e9d5a6f010445cc8b87a7cdb4d7cbee666c1288da3"
+checksum = "809e8dc61f6de73b46c85f4c96486310fe304c434cfa43669d7b40f711150908"
 dependencies = [
  "aho-corasick",
  "memchr",
@@ -247,18 +256,18 @@ checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
 [[package]]
 name = "serde"
-version = "1.0.210"
+version = "1.0.219"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c8e3592472072e6e22e0a54d5904d9febf8508f65fb8552499a1abc7d1078c3a"
+checksum = "5f0e2c6ed6606019b4e29e69dbaba95b11854410e5347d525002456dbbb786b6"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.210"
+version = "1.0.219"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "243902eda00fad750862fc144cea25caca5e20d615af0a81bee94ca738f1df1f"
+checksum = "5b0276cf7f2c73365f7157c8123c21cd9a50fbbd844757af28ca1f5925fc2a00"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -267,15 +276,15 @@ dependencies = [
 
 [[package]]
 name = "smallvec"
-version = "1.13.2"
+version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3c5e1a9a646d36c3599cd173a41282daf47c44583ad367b8e6837255952e5c67"
+checksum = "8917285742e9f3e1683f0a9c4e6b57960b7314d0b08d30d1ecd426713ee2eee9"
 
 [[package]]
 name = "syn"
-version = "2.0.79"
+version = "2.0.100"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "89132cd0bf050864e1d38dc3bbc07a0eb8e7530af26344d3d2bbbef83499f590"
+checksum = "b09a44accad81e1ba1cd74a32461ba89dee89095ba17b32f5d03683b1b1fc2a0"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -299,9 +308,9 @@ dependencies = [
 
 [[package]]
 name = "unicode-ident"
-version = "1.0.13"
+version = "1.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e91b56cd4cadaeb79bbf1a5645f6b4f8dc5bde8834ad5894a8db35fda9efa1fe"
+checksum = "5a5f39404a5da50712a4c1eecf25e90dd62b613502b7e925fd4e4d19b5c96512"
 
 [[package]]
 name = "windows-targets"
diff --git a/src/rust/Cargo.toml b/src/rust/Cargo.toml
index ef48a01..3b8c1b9 100644
--- a/src/rust/Cargo.toml
+++ b/src/rust/Cargo.toml
@@ -1,12 +1,13 @@
 [package]
-name = 'rtiktoken'
-version = '0.1.0'
-edition = '2021'
+name = "rtiktoken"
+version = "0.1.0"
+edition = "2021"
+rust-version = "1.65.0"
 
 [lib]
-crate-type = [ 'staticlib' ]
-name = 'rtiktoken'
+crate-type = [ "staticlib" ]
+name = "rtiktoken"
 
 [dependencies]
-extendr-api = { version = "0.7.1", default-features = false, features = ["result_list"] }
+extendr-api = { version = "0.8.0", default-features = false, features = ["result_list"] }
 tiktoken-rs = "0.5.9"
diff --git a/src/rust/vendor.tar.xz b/src/rust/vendor.tar.xz
index 574d380..6c348fe 100644
Binary files a/src/rust/vendor.tar.xz and b/src/rust/vendor.tar.xz differ
diff --git a/tools/config.R b/tools/config.R
new file mode 100644
index 0000000..13a5904
--- /dev/null
+++ b/tools/config.R
@@ -0,0 +1,77 @@
+# check the packages MSRV first
+source("tools/msrv.R")
+
+# check DEBUG and NOT_CRAN environment variables
+env_debug <- Sys.getenv("DEBUG")
+env_not_cran <- Sys.getenv("NOT_CRAN")
+
+# check if the vendored zip file exists
+vendor_exists <- file.exists("src/rust/vendor.tar.xz")
+
+is_not_cran <- env_not_cran != ""
+is_debug <- env_debug != ""
+
+if (is_debug) {
+  # if we have DEBUG then we set not cran to true
+  # CRAN is always release build
+  is_not_cran <- TRUE
+  message("Creating DEBUG build.")
+}
+
+if (!is_not_cran) {
+  message("Building for CRAN.")
+}
+
+# we set cran flags only if NOT_CRAN is empty and if
+# the vendored crates are present.
+.cran_flags <- ifelse(
+  !is_not_cran && vendor_exists,
+  "-j 2 --offline",
+  ""
+)
+
+# when DEBUG env var is present we use `--debug` build
+.profile <- ifelse(is_debug, "", "--release")
+.clean_targets <- ifelse(is_debug, "", "$(TARGET_DIR)")
+
+# when we are using a debug build we need to use target/debug instead of target/release
+.libdir <- ifelse(is_debug, "debug", "release")
+
+# read in the Makevars.in file
+is_windows <- .Platform[["OS.type"]] == "windows"
+
+# if windows we replace in the Makevars.win.in
+mv_fp <- ifelse(
+  is_windows,
+  "src/Makevars.win.in",
+  "src/Makevars.in"
+)
+
+# set the output file
+mv_ofp <- ifelse(
+  is_windows,
+  "src/Makevars.win",
+  "src/Makevars"
+)
+
+# delete the existing Makevars{.win}
+if (file.exists(mv_ofp)) {
+  message("Cleaning previous `", mv_ofp, "`.")
+  invisible(file.remove(mv_ofp))
+}
+
+# read as a single string
+mv_txt <- readLines(mv_fp)
+
+# replace placeholder values
+new_txt <- gsub("@CRAN_FLAGS@", .cran_flags, mv_txt) |>
+  gsub("@PROFILE@", .profile, x = _) |>
+  gsub("@CLEAN_TARGET@", .clean_targets, x = _) |>
+  gsub("@LIBDIR@", .libdir, x = _)
+
+message("Writing `", mv_ofp, "`.")
+con <- file(mv_ofp, open = "wb")
+writeLines(new_txt, con, sep = "\n")
+close(con)
+
+message("`tools/config.R` has finished.")
diff --git a/tools/msrv.R b/tools/msrv.R
index baa33aa..59a61ab 100644
--- a/tools/msrv.R
+++ b/tools/msrv.R
@@ -36,7 +36,7 @@ no_cargo_msg <- c(
   "Alternatively, you may install Cargo from your OS package manager:",
   " - Debian/Ubuntu: apt-get install cargo",
   " - Fedora/CentOS: dnf install cargo",
-  " - macOS: brew install rustc",
+  " - macOS: brew install rust",
   "-------------------------------------------------------------------"
 )
 
@@ -49,7 +49,7 @@ no_rustc_msg <- c(
   "Alternatively, you may install Rust from your OS package manager:",
   " - Debian/Ubuntu: apt-get install rustc",
   " - Fedora/CentOS: dnf install rustc",
-  " - macOS: brew install rustc",
+  " - macOS: brew install rust",
   "-------------------------------------------------------------------"
 )