[utils/build-script] Introduce '--extra-cmake-vars' to allow setting any CMake veriables when configuring the targets.

Author: akyrtzi

utils/build-script

@@ -700,6 +700,13 @@ the number of parallel build jobs to use""",
     a '\'"""),
         action="append", dest="extra_swift_args", default=[])
 
+    parser.add_argument(
+        "--extra-cmake-vars", help=textwrap.dedent("""
+    Pass through extra variables to CMake in the form of comma separated vars
+    'CMAKE_VAR1=YES,CMAKE_VAR2=/tmp'. Can be called multiple times to add
+    multiple such vars."""),
+        action="append", dest="extra_cmake_vars", default=[])
+
     parser.add_argument(
         "build_script_impl_args",
         help="",
@@ -1108,6 +1115,13 @@ the number of parallel build jobs to use""",
             "--extra-swift-args",
             ";".join(args.extra_swift_args)]
 
+    # If we have extra_cmake_args, combine all of them together and then add
+    # them as one command.
+    if args.extra_cmake_vars:
+        build_script_impl_args += [
+            "--extra-cmake-vars",
+            ",".join(args.extra_cmake_vars)]
+
     build_script_impl_args += args.build_script_impl_args
 
     # Unset environment variables that might affect how tools behave.

utils/build-script-impl

@@ -190,6 +190,7 @@ KNOWN_SETTINGS=(
     darwin-deployment-version-tvos    "9.0"      "minimum deployment target version for tvOS"
     darwin-deployment-version-watchos "2.0"      "minimum deployment target version for watchOS"
 
+    extra-cmake-vars            ""               "Extra variables to pass to CMake for all targets"
     extra-swift-args            ""               "Extra arguments to pass to swift modules which match regex. Assumed to be a flattened cmake list consisting of [module_regexp, args, module_regexp, args, ...]"
     sil-verify-all              "0"              "If enabled, run the SIL verifier after each transform when building Swift files during this build process"
     swift-enable-ast-verifier   "1"              "If enabled, and the assertions are enabled, the built Swift compiler will run the AST verifier every time it is invoked"
@@ -1197,6 +1198,16 @@ if [[ "${EXPORT_COMPILE_COMMANDS}" ]] ; then
     )
 fi
 
+if [[ "${EXTRA_CMAKE_VARS}" ]] ; then
+    for cmake_var in $(echo "${EXTRA_CMAKE_VARS}" | tr "," "\n")
+    do
+        COMMON_CMAKE_OPTIONS=(
+            "${COMMON_CMAKE_OPTIONS[@]}"
+            "-D${cmake_var}"
+        )
+    done
+fi
+
 if [[ "${DISTCC}" ]] ; then
     # On some platforms, 'pump' may be unrelated to distcc, in which case it's
     # called 'distcc-pump'.