modp_b64: Generate pkgconfig

Generate a pkgconfig file for this project.

BUG=b:176847216
TEST=emerge-zork modp_b64

Change-Id: Ie1058750a56da435aba949ecd31ed15e47d20f56
Reviewed-on: https://chromium-review.googlesource.com/c/aosp/platform/external/modp_b64/+/2648693
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Commit-Queue: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>

BUILD.gn

diff --git a/BUILD.gn b/BUILD.gn
index aceab6e..8ac3eda 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -2,9 +2,12 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//common-mk/pkg_config.gni")
+
 group("all") {
   deps = [
     ":modp_b64",
+    ":modp_b64_pkgconfig",
   ]
 
   if (use.fuzzer) {
@@ -32,6 +35,15 @@
   ]
 }
 
+generate_pkg_config("modp_b64_pkgconfig") {
+  name = "modp_b64"
+  output_name = "libmodp_b64"
+  description = "modp_b64 decoder."
+  version = "0"
+  deps = [":modp_b64"]
+  libs = ["-L${libdir}", "-lmodp_b64"]
+}
+
 # Fuzzers.
 if (use.fuzzer) {
   executable("modp_b64_decode_fuzzer") {