Only use clang specific directives when clang is used

This cl fixes GCC warnings caused by using clang specific directives.
Also ran git cl format on modified files.

Bug: chromium:1122889
Change-Id: Ibdaa84ab8162228ae40934fc9be14379ba89ca59
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/48148
Presubmit-Ready: Alexis Hétu <sugoi@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>

src/OpenGL/libEGL/BUILD.gn

diff --git a/src/OpenGL/libEGL/BUILD.gn b/src/OpenGL/libEGL/BUILD.gn
index e0803b6..602badd 100644
--- a/src/OpenGL/libEGL/BUILD.gn
+++ b/src/OpenGL/libEGL/BUILD.gn
@@ -39,8 +39,10 @@
     if (is_mac) {
       cflags += [ "-fvisibility=protected" ]
       defines += [ "EGLAPI=__attribute__((no_sanitize(\"function\")))" ]
-    } else {
+    } else if (is_clang) {
       defines += [ "EGLAPI=__attribute__((visibility(\"protected\"))) __attribute__((no_sanitize(\"function\")))" ]
+    } else {
+      defines += [ "EGLAPI= " ]
     }
   }
 }
@@ -82,9 +84,7 @@
     if (use_x11) {
       sources += [ "../../Main/libX11.cpp" ]
     }
-    inputs = [
-      "libEGL.lds",
-    ]
+    inputs = [ "libEGL.lds" ]
     ldflags =
         [ "-Wl,--version-script=" + rebase_path("libEGL.lds", root_build_dir) ]
   }

src/OpenGL/libGLESv2/BUILD.gn

diff --git a/src/OpenGL/libGLESv2/BUILD.gn b/src/OpenGL/libGLESv2/BUILD.gn
index aa2c86c..da2af9e 100644
--- a/src/OpenGL/libGLESv2/BUILD.gn
+++ b/src/OpenGL/libGLESv2/BUILD.gn
@@ -54,8 +54,10 @@
     if (is_mac) {
       cflags += [ "-fvisibility=protected" ]
       defines += [ "GL_APICALL=__attribute__((no_sanitize(\"function\")))" ]
-    } else {
+    } else if (is_clang) {
       defines += [ "GL_APICALL=__attribute__((visibility(\"protected\"))) __attribute__((no_sanitize(\"function\")))" ]
+    } else {
+      defines += [ "GL_APICALL= " ]
     }
   }
 }
@@ -114,9 +116,7 @@
     output_dir = "$root_out_dir/swiftshader"
   }
 
-  deps = [
-    ":swiftshader_libGLESv2_static",
-  ]
+  deps = [ ":swiftshader_libGLESv2_static" ]
 
   sources = [
     "entry_points.cpp",
@@ -131,9 +131,7 @@
           rebase_path("libGLESv2.exports", root_build_dir),
     ]
   } else if (is_linux) {
-    inputs = [
-      "libGLESv2.lds",
-    ]
+    inputs = [ "libGLESv2.lds" ]
     ldflags = [ "-Wl,--version-script=" +
                 rebase_path("libGLESv2.lds", root_build_dir) ]
   }