Fix issues with cc_configure

Fixing a few issues with cc_configure that I encountered.

* The argument for rpath should be -Wl,-rpath.
* cc_configure should consider CPLUS_INCLUDE_PATH. I ran into this problem when using
  a crosstool gcc which needs -I/usr/include.
* Check if -Wunused-but-set-parameter is available.

--
Change-Id: I73198b5b17674ecbf1b511e23fcc9331ca96c8e0
Reviewed-on: https://bazel-review.googlesource.com/#/c/3210/
MOS_MIGRATED_REVID=118763218

1 files changed, 17 insertions, 3 deletions

diff --git a/tools/cpp/cc_configure.bzl b/tools/cpp/cc_configure.bzl
index d73a388b06..fc8a5d713f 100644
--- a/tools/cpp/cc_configure.bzl
+++ b/tools/cpp/cc_configure.bzl
@@ -75,13 +75,25 @@ def _ld_library_paths(repository_ctx):
     result = []
     for p in repository_ctx.os.environ["LD_LIBRARY_PATH"].split(":"):
       p = str(repository_ctx.path(p))  # Normalize the path
-      result.append("-Wl,rpath," + p)
+      result.append("-Wl,-rpath," + p)
       result.append("-L" + p)
     return result
   else:
     return []
 
 
+def _cplus_include_paths(repository_ctx):
+  """Use ${CPLUS_INCLUDE_PATH} to compute the list of flags for cxxflag."""
+  if "CPLUS_INCLUDE_PATH" in repository_ctx.os.environ:
+    result = []
+    for p in repository_ctx.os.environ["CPLUS_INCLUDE_PATH"].split(":"):
+      p = str(repository_ctx.path(p))  # Normalize the path
+      result.append("-I" + p)
+    return result
+  else:
+    return []
+
+
 def _get_cpu_value(repository_ctx):
   """Compute the cpu_value based on the OS name."""
   os_name = repository_ctx.os.name.lower()
@@ -143,7 +155,9 @@ def _crosstool_content(repository_ctx, cc, cpu_value, darwin):
       "target_libc": "macosx" if darwin else "local",
       "target_cpu": cpu_value,
       "target_system_name": "local",
-      "cxx_flag": "-std=c++0x",
+      "cxx_flag": [
+          "-std=c++0x",
+      ] + _cplus_include_paths(repository_ctx),
       "linker_flag": [
           "-lstdc++",
           # Anticipated future default.
@@ -185,10 +199,10 @@ def _crosstool_content(repository_ctx, cc, cpu_value, darwin):
           "-Wall",
           # Enable a few more warnings that aren't part of -Wall.
       ] + (["-Wthread-safety", "-Wself-assign"] if darwin else [
-          "-Wunused-but-set-parameter",
           # Disable some that are problematic.
           "-Wl,-z,-relro,-z,now"
       ]) + (
+          _add_option_if_supported(repository_ctx, cc, "-Wunused-but-set-parameter") +
           # has false positives
           _add_option_if_supported(repository_ctx, cc, "-Wno-free-nonheap-object") +
           # Enable coloring even if there's no attached terminal. Bazel removes the