Added README describing toolchain patches (#1349)

Author: UebelAndre

toolchains/built_toolchains.bzl

@@ -33,17 +33,11 @@ def built_toolchains(cmake_version, make_version, ninja_version, meson_version,
 
     Args:
         cmake_version: The CMake version to build
-
         make_version: The Make version to build
-
         ninja_version: The Ninja version to build
-
         meson_version: The Meson version to build
-
         pkgconfig_version: The pkg-config version to build
-
         register_toolchains: If true, registers the toolchains via native.register_toolchains. Used by bzlmod
-
         register_built_pkgconfig_toolchain: If true, the built pkgconfig toolchain will be registered.
     """
     _cmake_toolchain(cmake_version, register_toolchains)
@@ -73,7 +67,7 @@ def _cmake_toolchain(version, register_toolchains):
             strip_prefix = prefix,
             urls = urls,
             patches = [
-                Label("//toolchains:cmake-c++11.patch"),
+                Label("//toolchains/patches:cmake-c++11.patch"),
             ],
         )
         return
@@ -118,7 +112,7 @@ def _make_toolchain(version, register_toolchains):
             http_archive,
             name = "gnumake_src",
             build_file_content = _ALL_CONTENT,
-            patches = [Label("//toolchains:make-reproducible-bootstrap.patch")],
+            patches = [Label("//toolchains/patches:make-reproducible-bootstrap.patch")],
             sha256 = "e05fdde47c5f7ca45cb697e973894ff4f5d79e13b750ed57d7b66d8defc78e19",
             strip_prefix = "make-4.3",
             urls = [
@@ -340,13 +334,13 @@ cc_import(
             # The patch is required as bazel does not provide the VCINSTALLDIR or WINDOWSSDKDIR vars
             patches = [
                 # This patch is required as bazel does not provide the VCINSTALLDIR or WINDOWSSDKDIR vars
-                Label("//toolchains:pkgconfig-detectenv.patch"),
+                Label("//toolchains/patches:pkgconfig-detectenv.patch"),
 
                 # This patch is required as rules_foreign_cc runs in MSYS2 on Windows and MSYS2's "mkdir" is used
-                Label("//toolchains:pkgconfig-makefile-vc.patch"),
+                Label("//toolchains/patches:pkgconfig-makefile-vc.patch"),
 
                 # This patch fixes explicit integer conversion which causes errors in clang >= 15 and gcc >= 14
-                Label("//toolchains:pkgconfig-builtin-glib-int-conversion.patch"),
+                Label("//toolchains/patches:pkgconfig-builtin-glib-int-conversion.patch"),
             ],
             urls = [
                 "https://pkgconfig.freedesktop.org/releases/pkg-config-0.29.2.tar.gz",

toolchains/patches/BUILD.bazel

@@ -0,0 +1,21 @@
+# Foreign CC toolchain patches
+
+## [cmake-c++11.patch](./cmake-c++11.patch)
+
+See <https://discourse.cmake.org/t/cmake-error-at-cmakelists-txt-117-message-the-c-compiler-does-not-support-c-11-e-g-std-unique-ptr/3774/8>
+
+## [make-reproducible-bootstrap.patch](./make-reproducible-bootstrap.patch)
+
+This patch avoids reliance on host installed tools for bootstrapping make.
+
+## [pkgconfig-builtin-glib-int-conversion.patch](./pkgconfig-builtin-glib-int-conversion.patch)
+
+This patch fixes explicit integer conversion which causes errors in `clang >= 15` and `gcc >= 14`
+
+## [pkgconfig-detectenv.patch](./pkgconfig-detectenv.patch)
+
+This patch is required as bazel does not provide the VCINSTALLDIR or WINDOWSSDKDIR vars
+
+## [pkgconfig-makefile-vc.patch](./pkgconfig-makefile-vc.patch)
+
+This patch is required as rules_foreign_cc runs in MSYS2 on Windows and MSYS2's "mkdir" is used

toolchains/patches/README.md

@@ -1,5 +1,3 @@
-See <https://discourse.cmake.org/t/cmake-error-at-cmakelists-txt-117-message-the-c-compiler-does-not-support-c-11-e-g-std-unique-ptr/3774/8>
-
 --- CMakeLists.txt	2023-01-24 13:46:17.000000000 -0800
 +++ CMakeLists.txt	2023-01-24 13:46:43.000000000 -0800
 @@ -96,10 +96,6 @@