Improving detection of ccache on Mac

Before this commit, ccache where only used on Mac when
`OSXCROSS_ROOT` was defined. Now, it could be used even
when that envirnment variable is not defined.

methods.py

@@ -657,12 +657,14 @@ def detect_darwin_sdk_path(platform, env):
 
 
 def is_apple_clang(env):
+    import shlex
+
     if env["platform"] not in ["macos", "ios"]:
         return False
     if not using_clang(env):
         return False
     try:
-        version = subprocess.check_output([env.subst(env["CXX"]), "--version"]).strip().decode("utf-8")
+        version = subprocess.check_output(shlex.split(env.subst(env["CXX"])) + ["--version"]).strip().decode("utf-8")
     except (subprocess.CalledProcessError, OSError):
         print_warning("Couldn't parse CXX environment variable to infer compiler version.")
         return False
@@ -677,6 +679,8 @@ def get_compiler_version(env):
     - metadata1, metadata2: Extra information
     - date: Date of the build
     """
+    import shlex
+
     ret = {
         "major": -1,
         "minor": -1,
@@ -727,7 +731,7 @@ def get_compiler_version(env):
     # Clang used to return hardcoded 4.2.1: # https://reviews.llvm.org/D56803
     try:
         version = subprocess.check_output(
-            [env.subst(env["CXX"]), "--version"], shell=(os.name == "nt"), encoding="utf-8"
+            shlex.split(env.subst(env["CXX"])) + ["--version"], shell=(os.name == "nt"), encoding="utf-8"
         ).strip()
     except (subprocess.CalledProcessError, OSError):
         print_warning("Couldn't parse CXX environment variable to infer compiler version.")

platform/macos/detect.py

@@ -108,6 +108,10 @@ def configure(env: "SConsEnvironment"):
 
     env.Append(CCFLAGS=["-fobjc-arc"])
 
+    ccache_path = os.environ.get("CCACHE", "")
+    if ccache_path != "":
+        ccache_path = ccache_path + " "
+
     if "osxcross" not in env:  # regular native build
         if env["macports_clang"] != "no":
             mpprefix = os.environ.get("MACPORTS_PREFIX", "/opt/local")
@@ -118,8 +122,8 @@ def configure(env: "SConsEnvironment"):
             env["RANLIB"] = mpprefix + "/libexec/llvm-" + mpclangver + "/bin/llvm-ranlib"
             env["AS"] = mpprefix + "/libexec/llvm-" + mpclangver + "/bin/llvm-as"
         else:
-            env["CC"] = "clang"
-            env["CXX"] = "clang++"
+            env["CC"] = ccache_path + "clang"
+            env["CXX"] = ccache_path + "clang++"
 
         detect_darwin_sdk_path("macos", env)
         env.Append(CCFLAGS=["-isysroot", "$MACOS_SDK_PATH"])
@@ -132,15 +136,8 @@ def configure(env: "SConsEnvironment"):
         else:
             basecmd = root + "/target/bin/x86_64-apple-" + env["osxcross_sdk"] + "-"
 
-        ccache_path = os.environ.get("CCACHE")
-        if ccache_path is None:
-            env["CC"] = basecmd + "cc"
-            env["CXX"] = basecmd + "c++"
-        else:
-            # there aren't any ccache wrappers available for macOS cross-compile,
-            # to enable caching we need to prepend the path to the ccache binary
-            env["CC"] = ccache_path + " " + basecmd + "cc"
-            env["CXX"] = ccache_path + " " + basecmd + "c++"
+        env["CC"] = ccache_path + basecmd + "cc"
+        env["CXX"] = ccache_path + basecmd + "c++"
         env["AR"] = basecmd + "ar"
         env["RANLIB"] = basecmd + "ranlib"
         env["AS"] = basecmd + "as"