Add gcc-5 constraint value [BUILD-650] (#65)

* Add gcc-5 constraint value

* Forward visibility in cc_static_libarary

* Set default value for visibility

Author: krisukox

cc/constraints/BUILD.bazel

@@ -4,6 +4,11 @@ package(default_visibility = ["//visibility:public"])
 
 constraint_setting(name = "compiler")
 
+constraint_value(
+    name = "gcc-5",
+    constraint_setting = ":compiler",
+)
+
 constraint_value(
     name = "gcc-6",
     constraint_setting = ":compiler",

cc/copts.bzl

@@ -48,3 +48,4 @@ DEFAULT_COPTS = [
 
 GCC6_DISABLED_COPTS = ["-Wimplicit-fallthrough"]
 GCC6_COPTS = [copt for copt in DEFAULT_COPTS if copt not in GCC6_DISABLED_COPTS]
+GCC5_COPTS = GCC6_COPTS

cc/defs.bzl

@@ -12,7 +12,7 @@
 
 load("//tools:stamp_file.bzl", "stamp_file")
 load(":utils.bzl", "construct_local_include")
-load(":copts.bzl", "DEFAULT_COPTS", "GCC6_COPTS")
+load(":copts.bzl", "DEFAULT_COPTS", "GCC5_COPTS", "GCC6_COPTS")
 load(":cc_static_library.bzl", _cc_static_library = "cc_static_library")
 
 # Name for a unit test
@@ -49,6 +49,7 @@ def _cxx_standard(default, override):
 def _common_cc_opts(nocopts, pedantic = False):
     return select({
         Label("//cc/constraints:gcc-6"): [copt for copt in GCC6_COPTS if copt not in nocopts],
+        Label("//cc/constraints:gcc-5"): [copt for copt in GCC5_COPTS if copt not in nocopts],
         "//conditions:default": [copt for copt in DEFAULT_COPTS if copt not in nocopts],
     }) + ["-pedantic"] if pedantic else []
 
@@ -137,7 +138,7 @@ def cc_stamped_library(name, out, template, hdrs, includes, defaults, visibility
         visibility = visibility,
     )
 
-def cc_static_library(name, deps):
+def cc_static_library(name, deps, visibility = ["//visibility:private"]):
     _cc_static_library(
         name = name,
         deps = deps,
@@ -146,6 +147,7 @@ def cc_static_library(name, deps):
             "@platforms//os:macos": ["@platforms//:incompatible"],
             "//conditions:default": [],
         }),
+        visibility = visibility,
     )
 
 def swift_c_library(**kwargs):