diff --git a/libraries/source/cxxtest-4.4/build.sh b/libraries/source/cxxtest-4.4/build.sh
index 3243836ecb..fe953dd108 100755
--- a/libraries/source/cxxtest-4.4/build.sh
+++ b/libraries/source/cxxtest-4.4/build.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 set -e
 
+: "${TAR:=tar}"
+
 cd "$(dirname "$0")"
 
 PV=4.4
@@ -40,7 +42,7 @@ fi
 
 # unpack
 rm -Rf "cxxtest-${PV}"
-tar -xf "cxxtest-${PV}.tar.gz"
+"${TAR}" -xf "cxxtest-${PV}.tar.gz"
 
 # patch
 patch -d "cxxtest-${PV}" -p1 <patches/0001-Add-Debian-python3-patch.patch
diff --git a/libraries/source/fcollada/build.sh b/libraries/source/fcollada/build.sh
index 4ba98b9d2a..2e42ba4647 100755
--- a/libraries/source/fcollada/build.sh
+++ b/libraries/source/fcollada/build.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 set -e
 
+: "${TAR:=tar}"
+
 cd "$(dirname "$0")"
 
 PV=28209
@@ -10,7 +12,7 @@ fetch()
 {
 	rm -Rf fcollada-${PV}
 	svn export https://svn.wildfiregames.com/public/source-libs/trunk/fcollada@${PV} fcollada-${PV}
-	tar cJf fcollada-${PV}.tar.xz fcollada-${PV}
+	"${TAR}" cJf fcollada-${PV}.tar.xz fcollada-${PV}
 	rm -R fcollada-${PV}
 }
 
@@ -42,7 +44,7 @@ fi
 
 # unpack
 rm -Rf fcollada-${PV}
-tar xf fcollada-${PV}.tar.xz
+"${TAR}" xf fcollada-${PV}.tar.xz
 
 # build
 (
diff --git a/libraries/source/nvtt/build.sh b/libraries/source/nvtt/build.sh
index 47299730fe..8a00df89f3 100755
--- a/libraries/source/nvtt/build.sh
+++ b/libraries/source/nvtt/build.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 set -e
 
+: "${TAR:=tar}"
+
 cd "$(dirname "$0")"
 
 PV=28209
@@ -10,7 +12,7 @@ fetch()
 {
 	rm -Rf nvtt-${PV}
 	svn export https://svn.wildfiregames.com/public/source-libs/trunk/nvtt@${PV} nvtt-${PV}
-	tar cJf nvtt-${PV}.tar.xz nvtt-${PV}
+	"${TAR}" cJf nvtt-${PV}.tar.xz nvtt-${PV}
 	rm -R nvtt-${PV}
 }
 
@@ -42,7 +44,7 @@ fi
 
 # unpack
 rm -Rf nvtt-${PV}
-tar xf nvtt-${PV}.tar.xz
+"${TAR}" xf nvtt-${PV}.tar.xz
 
 # build
 (
diff --git a/libraries/source/premake-core/build.sh b/libraries/source/premake-core/build.sh
index 1433a57a50..f6d50d8e92 100755
--- a/libraries/source/premake-core/build.sh
+++ b/libraries/source/premake-core/build.sh
@@ -4,6 +4,7 @@ set -e
 : "${OS:=$(uname -s || true)}"
 : "${MAKE:=make}"
 : "${JOBS:=-j1}"
+: "${TAR:=tar}"
 
 cd "$(dirname "$0")"
 
@@ -44,7 +45,7 @@ fi
 
 # unpack
 rm -Rf "premake-core-${PV}"
-tar -xf "premake-core-${PV}.tar.gz"
+"${TAR}" -xf "premake-core-${PV}.tar.gz"
 
 # patch
 # ffcb7790f013bdceacc14ba5fda1c5cd107aac08
diff --git a/libraries/source/spidermonkey/build.sh b/libraries/source/spidermonkey/build.sh
index c0d2e36cd0..d3c21fe4ea 100755
--- a/libraries/source/spidermonkey/build.sh
+++ b/libraries/source/spidermonkey/build.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 set -e
 
+: "${TAR:=tar}"
+
 cd "$(dirname "$0")"
 
 # This should match the version in config/milestone.txt
@@ -47,7 +49,7 @@ fi
 
 # unpack
 rm -Rf "${FOLDER}"
-tar xfJ "${FOLDER}.tar.xz"
+"${TAR}" xfJ "${FOLDER}.tar.xz"
 
 # patch
 (
diff --git a/libraries/source/spirv-reflect/build.sh b/libraries/source/spirv-reflect/build.sh
index c5169b5bfc..18874174c1 100755
--- a/libraries/source/spirv-reflect/build.sh
+++ b/libraries/source/spirv-reflect/build.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 set -e
 
+: "${TAR:=tar}"
+
 cd "$(dirname "$0")"
 
 PV=1.3.290.0
@@ -40,7 +42,7 @@ fi
 
 # unpack
 rm -Rf "SPIRV-Reflect-vulkan-sdk-${PV}"
-tar xf "vulkan-sdk-${PV}.tar.gz"
+"${TAR}" xf "vulkan-sdk-${PV}.tar.gz"
 
 # configure
 cmake -B build -S "SPIRV-Reflect-vulkan-sdk-${PV}" \