Allow most third_party targets to use system libraries if asked.

This extends the pattern in freetype2 to expat, icu, libjpeg-turbo, libpng, libwebp, and zlib, and gives all these an arg to control which to use.

Homebrew doesn't have dng_sdk, piex, or sftnly, or I'd have done the same for them too.

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4260

DOCS_PREVIEW= https://skia.org/?cl=4260

Change-Id: I82e780502bf2217336e791787f172a6fc8f55460
Reviewed-on: https://skia-review.googlesource.com/4260
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Hal Canary <halcanary@google.com>

1 files changed, 55 insertions, 48 deletions

diff --git a/third_party/libjpeg-turbo/BUILD.gn b/third_party/libjpeg-turbo/BUILD.gn
index 95a381b8e6..c0382a719c 100644
--- a/third_party/libjpeg-turbo/BUILD.gn
+++ b/third_party/libjpeg-turbo/BUILD.gn
@@ -4,58 +4,65 @@
 # found in the LICENSE file.
 
 declare_args() {
+  skia_use_system_libjpeg_turbo = false
 }
 
 import("../third_party.gni")
 
-third_party("libjpeg") {
-  public_include_dirs = [ "../externals/libjpeg-turbo" ]
+if (skia_use_system_libjpeg_turbo) {
+  system("libjpeg") {
+    libs = [ "jpeg" ]
+  }
+} else {
+  third_party("libjpeg") {
+    public_include_dirs = [ "../externals/libjpeg-turbo" ]
 
-  defines = [ "TURBO_FOR_WINDOWS" ]
+    defines = [ "TURBO_FOR_WINDOWS" ]
 
-  sources = [
-    "../externals/libjpeg-turbo/jcapimin.c",
-    "../externals/libjpeg-turbo/jcapistd.c",
-    "../externals/libjpeg-turbo/jccoefct.c",
-    "../externals/libjpeg-turbo/jccolor.c",
-    "../externals/libjpeg-turbo/jcdctmgr.c",
-    "../externals/libjpeg-turbo/jchuff.c",
-    "../externals/libjpeg-turbo/jcinit.c",
-    "../externals/libjpeg-turbo/jcmainct.c",
-    "../externals/libjpeg-turbo/jcmarker.c",
-    "../externals/libjpeg-turbo/jcmaster.c",
-    "../externals/libjpeg-turbo/jcomapi.c",
-    "../externals/libjpeg-turbo/jcparam.c",
-    "../externals/libjpeg-turbo/jcphuff.c",
-    "../externals/libjpeg-turbo/jcprepct.c",
-    "../externals/libjpeg-turbo/jcsample.c",
-    "../externals/libjpeg-turbo/jdapimin.c",
-    "../externals/libjpeg-turbo/jdapistd.c",
-    "../externals/libjpeg-turbo/jdcoefct.c",
-    "../externals/libjpeg-turbo/jdcolor.c",
-    "../externals/libjpeg-turbo/jddctmgr.c",
-    "../externals/libjpeg-turbo/jdhuff.c",
-    "../externals/libjpeg-turbo/jdinput.c",
-    "../externals/libjpeg-turbo/jdmainct.c",
-    "../externals/libjpeg-turbo/jdmarker.c",
-    "../externals/libjpeg-turbo/jdmaster.c",
-    "../externals/libjpeg-turbo/jdmerge.c",
-    "../externals/libjpeg-turbo/jdphuff.c",
-    "../externals/libjpeg-turbo/jdpostct.c",
-    "../externals/libjpeg-turbo/jdsample.c",
-    "../externals/libjpeg-turbo/jerror.c",
-    "../externals/libjpeg-turbo/jfdctflt.c",
-    "../externals/libjpeg-turbo/jfdctfst.c",
-    "../externals/libjpeg-turbo/jfdctint.c",
-    "../externals/libjpeg-turbo/jidctflt.c",
-    "../externals/libjpeg-turbo/jidctfst.c",
-    "../externals/libjpeg-turbo/jidctint.c",
-    "../externals/libjpeg-turbo/jidctred.c",
-    "../externals/libjpeg-turbo/jmemmgr.c",
-    "../externals/libjpeg-turbo/jmemnobs.c",
-    "../externals/libjpeg-turbo/jquant1.c",
-    "../externals/libjpeg-turbo/jquant2.c",
-    "../externals/libjpeg-turbo/jsimd_none.c",
-    "../externals/libjpeg-turbo/jutils.c",
-  ]
+    sources = [
+      "../externals/libjpeg-turbo/jcapimin.c",
+      "../externals/libjpeg-turbo/jcapistd.c",
+      "../externals/libjpeg-turbo/jccoefct.c",
+      "../externals/libjpeg-turbo/jccolor.c",
+      "../externals/libjpeg-turbo/jcdctmgr.c",
+      "../externals/libjpeg-turbo/jchuff.c",
+      "../externals/libjpeg-turbo/jcinit.c",
+      "../externals/libjpeg-turbo/jcmainct.c",
+      "../externals/libjpeg-turbo/jcmarker.c",
+      "../externals/libjpeg-turbo/jcmaster.c",
+      "../externals/libjpeg-turbo/jcomapi.c",
+      "../externals/libjpeg-turbo/jcparam.c",
+      "../externals/libjpeg-turbo/jcphuff.c",
+      "../externals/libjpeg-turbo/jcprepct.c",
+      "../externals/libjpeg-turbo/jcsample.c",
+      "../externals/libjpeg-turbo/jdapimin.c",
+      "../externals/libjpeg-turbo/jdapistd.c",
+      "../externals/libjpeg-turbo/jdcoefct.c",
+      "../externals/libjpeg-turbo/jdcolor.c",
+      "../externals/libjpeg-turbo/jddctmgr.c",
+      "../externals/libjpeg-turbo/jdhuff.c",
+      "../externals/libjpeg-turbo/jdinput.c",
+      "../externals/libjpeg-turbo/jdmainct.c",
+      "../externals/libjpeg-turbo/jdmarker.c",
+      "../externals/libjpeg-turbo/jdmaster.c",
+      "../externals/libjpeg-turbo/jdmerge.c",
+      "../externals/libjpeg-turbo/jdphuff.c",
+      "../externals/libjpeg-turbo/jdpostct.c",
+      "../externals/libjpeg-turbo/jdsample.c",
+      "../externals/libjpeg-turbo/jerror.c",
+      "../externals/libjpeg-turbo/jfdctflt.c",
+      "../externals/libjpeg-turbo/jfdctfst.c",
+      "../externals/libjpeg-turbo/jfdctint.c",
+      "../externals/libjpeg-turbo/jidctflt.c",
+      "../externals/libjpeg-turbo/jidctfst.c",
+      "../externals/libjpeg-turbo/jidctint.c",
+      "../externals/libjpeg-turbo/jidctred.c",
+      "../externals/libjpeg-turbo/jmemmgr.c",
+      "../externals/libjpeg-turbo/jmemnobs.c",
+      "../externals/libjpeg-turbo/jquant1.c",
+      "../externals/libjpeg-turbo/jquant2.c",
+      "../externals/libjpeg-turbo/jsimd_none.c",
+      "../externals/libjpeg-turbo/jutils.c",
+    ]
+  }
 }