From 9ea46247048f861f088f09541cd434aeb16e6f9c Mon Sep 17 00:00:00 2001
From: James Hilliard <james.hilliard1@gmail.com>
Date: Tue, 15 Mar 2022 23:31:59 -0600
Subject: [PATCH 1/2] Search pkg-config system libs/cflags.

We need to search the system paths as well from pkg-config for
some packages to be found properly.
---
 setup.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/setup.py b/setup.py
index 9a05e5105..d41aedbd6 100755
--- a/setup.py
+++ b/setup.py
@@ -252,8 +252,8 @@ def _cmd_exists(cmd):
 def _pkg_config(name):
     try:
         command = os.environ.get("PKG_CONFIG", "pkg-config")
-        command_libs = [command, "--libs-only-L", name]
-        command_cflags = [command, "--cflags-only-I", name]
+        command_libs = [command, "--libs-only-L", "--keep-system-libs", name]
+        command_cflags = [command, "--cflags-only-I", "--keep-system-cflags", name]
         if not DEBUG:
             command_libs.append("--silence-errors")
             command_cflags.append("--silence-errors")

From 6ec9dfb9c0bc04a5504231887a3fb86cb8863721 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Sat, 23 Apr 2022 21:58:30 +1000
Subject: [PATCH 2/2] If an exception is raised, try again without system paths

---
 setup.py | 48 ++++++++++++++++++++++++++----------------------
 1 file changed, 26 insertions(+), 22 deletions(-)

diff --git a/setup.py b/setup.py
index d41aedbd6..37bb2ceb8 100755
--- a/setup.py
+++ b/setup.py
@@ -250,28 +250,32 @@ def _cmd_exists(cmd):
 
 
 def _pkg_config(name):
-    try:
-        command = os.environ.get("PKG_CONFIG", "pkg-config")
-        command_libs = [command, "--libs-only-L", "--keep-system-libs", name]
-        command_cflags = [command, "--cflags-only-I", "--keep-system-cflags", name]
-        if not DEBUG:
-            command_libs.append("--silence-errors")
-            command_cflags.append("--silence-errors")
-        libs = (
-            subprocess.check_output(command_libs)
-            .decode("utf8")
-            .strip()
-            .replace("-L", "")
-        )
-        cflags = (
-            subprocess.check_output(command_cflags)
-            .decode("utf8")
-            .strip()
-            .replace("-I", "")
-        )
-        return libs, cflags
-    except Exception:
-        pass
+    command = os.environ.get("PKG_CONFIG", "pkg-config")
+    for keep_system in (True, False):
+        try:
+            command_libs = [command, "--libs-only-L", name]
+            command_cflags = [command, "--cflags-only-I", name]
+            if keep_system:
+                command_libs.append("--keep-system-libs")
+                command_cflags.append("--keep-system-cflags")
+            if not DEBUG:
+                command_libs.append("--silence-errors")
+                command_cflags.append("--silence-errors")
+            libs = (
+                subprocess.check_output(command_libs)
+                .decode("utf8")
+                .strip()
+                .replace("-L", "")
+            )
+            cflags = (
+                subprocess.check_output(command_cflags)
+                .decode("utf8")
+                .strip()
+                .replace("-I", "")
+            )
+            return libs, cflags
+        except Exception:
+            pass
 
 
 class pil_build_ext(build_ext):