Make it work on Windows.

BUILD.bazel

@@ -10,7 +10,9 @@ licenses(["notice"])  # Mixed: BSD, MIT, Khronos, Apache 2.0
 
 exports_files(["LICENSE"])
 
-COMMON_COPTS = [
+COMMON_COPTS = select({
+    "@bazel_tools//src/conditions:windows": [""],
+    "//conditions:default": [
         "-Wall",
         "-Wuninitialized",
         "-Wunused",
@@ -24,7 +26,8 @@ COMMON_COPTS = [
         "-fvisibility-inlines-hidden",
         "-fno-exceptions",
         "-fno-rtti",
-]
+    ],
+})
 
 cc_library(
     name = "glslang",
@@ -43,8 +46,12 @@ cc_library(
         ],
     ) + [
         "OGLCompilersDLL/InitializeDll.cpp",
-        "glslang/OSDependent/Unix/ossource.cpp",
-    ],
+    ] + select({
+        "@bazel_tools//src/conditions:windows":
+	    ["glslang/OSDependent/Windows/ossource.cpp"],
+        "//conditions:default":
+	    ["glslang/OSDependent/Unix/ossource.cpp"],
+    }),
     hdrs = glob([
         "glslang/Include/*.h",
         "glslang/MachineIndependent/*.h",
@@ -61,13 +68,12 @@ cc_library(
         "AMD_EXTENSIONS",
         "ENABLE_HLSL=0",
         "ENABLE_OPT=0",
-        "GLSLANG_OSINCLUDE_UNIX",
         "NV_EXTENSIONS",
     ],
-    linkopts = [
-        "-lm",
-        "-lpthread",
-    ],
+    linkopts = select({
+        "@bazel_tools//src/conditions:windows": [""],
+        "//conditions:default": ["-lm", "-lpthread"],
+    }),
     linkstatic = 1,
 )
 
@@ -125,7 +131,10 @@ cc_library(
     ],
     copts = COMMON_COPTS,
     includes = ["SPIRV"],
-    linkopts = ["-lm"],
+    linkopts = select({
+        "@bazel_tools//src/conditions:windows": [""],
+        "//conditions:default": ["-lm"],
+    }),
     linkstatic = 1,
     deps = [
         ":SPIRV_headers",