Do not depend on pkg-config.

Some systems do not have it by default; let's use libpng-config if
pkg-config is unavailable.

Fixes #110.

Author: robryk

guetzli.make

@@ -19,12 +19,12 @@ ifeq ($(config),release)
   INCLUDES += -I. -Ithird_party/butteraugli
   FORCE_INCLUDE +=
   ALL_CPPFLAGS += $(CPPFLAGS) -MMD -MP $(DEFINES) $(INCLUDES)
-  ALL_CFLAGS += $(CFLAGS) $(ALL_CPPFLAGS) -O3 -g `pkg-config --cflags libpng`
-  ALL_CXXFLAGS += $(CXXFLAGS) $(ALL_CPPFLAGS) -O3 -g -std=c++11 `pkg-config --cflags libpng`
+  ALL_CFLAGS += $(CFLAGS) $(ALL_CPPFLAGS) -O3 -g `pkg-config --cflags libpng || libpng-config --cflags`
+  ALL_CXXFLAGS += $(CXXFLAGS) $(ALL_CPPFLAGS) -O3 -g -std=c++11 `pkg-config --cflags libpng || libpng-config --cflags`
   ALL_RESFLAGS += $(RESFLAGS) $(DEFINES) $(INCLUDES)
   LIBS +=
   LDDEPS +=
-  ALL_LDFLAGS += $(LDFLAGS) `pkg-config --libs libpng`
+  ALL_LDFLAGS += $(LDFLAGS) `pkg-config --libs libpng || libpng-config --ldflags`
   LINKCMD = $(CXX) -o "$@" $(OBJECTS) $(RESOURCES) $(ALL_LDFLAGS) $(LIBS)
   define PREBUILDCMDS
   endef
@@ -46,12 +46,12 @@ ifeq ($(config),debug)
   INCLUDES += -I. -Ithird_party/butteraugli
   FORCE_INCLUDE +=
   ALL_CPPFLAGS += $(CPPFLAGS) -MMD -MP $(DEFINES) $(INCLUDES)
-  ALL_CFLAGS += $(CFLAGS) $(ALL_CPPFLAGS) -g `pkg-config --cflags libpng`
-  ALL_CXXFLAGS += $(CXXFLAGS) $(ALL_CPPFLAGS) -g -std=c++11 `pkg-config --cflags libpng`
+  ALL_CFLAGS += $(CFLAGS) $(ALL_CPPFLAGS) -g `pkg-config --cflags libpng || libpng-config --cflags`
+  ALL_CXXFLAGS += $(CXXFLAGS) $(ALL_CPPFLAGS) -g -std=c++11 `pkg-config --cflags libpng || libpng-config --cflags`
   ALL_RESFLAGS += $(RESFLAGS) $(DEFINES) $(INCLUDES)
   LIBS +=
   LDDEPS +=
-  ALL_LDFLAGS += $(LDFLAGS) `pkg-config --libs libpng`
+  ALL_LDFLAGS += $(LDFLAGS) `pkg-config --libs libpng || libpng-config --ldflags`
   LINKCMD = $(CXX) -o "$@" $(OBJECTS) $(RESOURCES) $(ALL_LDFLAGS) $(LIBS)
   define PREBUILDCMDS
   endef

guetzli_static.make

@@ -19,12 +19,12 @@ ifeq ($(config),release)
   INCLUDES += -I. -Ithird_party/butteraugli
   FORCE_INCLUDE +=
   ALL_CPPFLAGS += $(CPPFLAGS) -MMD -MP $(DEFINES) $(INCLUDES)
-  ALL_CFLAGS += $(CFLAGS) $(ALL_CPPFLAGS) -O3 -g `pkg-config --static --cflags libpng`
-  ALL_CXXFLAGS += $(CXXFLAGS) $(ALL_CPPFLAGS) -O3 -g -std=c++11 `pkg-config --static --cflags libpng`
+  ALL_CFLAGS += $(CFLAGS) $(ALL_CPPFLAGS) -O3 -g `pkg-config --static --cflags libpng || libpng-config --static --cflags`
+  ALL_CXXFLAGS += $(CXXFLAGS) $(ALL_CPPFLAGS) -O3 -g -std=c++11 `pkg-config --static --cflags libpng || libpng-config --static --cflags`
   ALL_RESFLAGS += $(RESFLAGS) $(DEFINES) $(INCLUDES)
   LIBS +=
   LDDEPS +=
-  ALL_LDFLAGS += $(LDFLAGS) `pkg-config --static --libs libpng`
+  ALL_LDFLAGS += $(LDFLAGS) `pkg-config --static --libs libpng || libpng-config --static --ldflags`
   LINKCMD = $(AR) -rcs "$@" $(OBJECTS)
   define PREBUILDCMDS
   endef
@@ -46,12 +46,12 @@ ifeq ($(config),debug)
   INCLUDES += -I. -Ithird_party/butteraugli
   FORCE_INCLUDE +=
   ALL_CPPFLAGS += $(CPPFLAGS) -MMD -MP $(DEFINES) $(INCLUDES)
-  ALL_CFLAGS += $(CFLAGS) $(ALL_CPPFLAGS) -g `pkg-config --static --cflags libpng`
-  ALL_CXXFLAGS += $(CXXFLAGS) $(ALL_CPPFLAGS) -g -std=c++11 `pkg-config --static --cflags libpng`
+  ALL_CFLAGS += $(CFLAGS) $(ALL_CPPFLAGS) -g `pkg-config --static --cflags libpng || libpng-config --static --cflags`
+  ALL_CXXFLAGS += $(CXXFLAGS) $(ALL_CPPFLAGS) -g -std=c++11 `pkg-config --static --cflags libpng || libpng-config --static --cflags`
   ALL_RESFLAGS += $(RESFLAGS) $(DEFINES) $(INCLUDES)
   LIBS +=
   LDDEPS +=
-  ALL_LDFLAGS += $(LDFLAGS) `pkg-config --static --libs libpng`
+  ALL_LDFLAGS += $(LDFLAGS) `pkg-config --static --libs libpng || libpng-config --static --ldflags`
   LINKCMD = $(AR) -rcs "$@" $(OBJECTS)
   define PREBUILDCMDS
   endef

premake5.lua

@@ -33,14 +33,14 @@ workspace "guetzli"
       }
     removefiles "guetzli/guetzli.cc"
     filter "action:gmake"
-      linkoptions { "`pkg-config --static --libs libpng`" }
-      buildoptions { "`pkg-config --static --cflags libpng`" }
+      linkoptions { "`pkg-config --static --libs libpng || libpng-config --static --ldflags`" }
+      buildoptions { "`pkg-config --static --cflags libpng || libpng-config --static --cflags`" }
 
   project "guetzli"
     kind "ConsoleApp"
     filter "action:gmake"
-      linkoptions { "`pkg-config --libs libpng`" }
-      buildoptions { "`pkg-config --cflags libpng`" }
+      linkoptions { "`pkg-config --libs libpng || libpng-config --ldflags`" }
+      buildoptions { "`pkg-config --cflags libpng || libpng-config --cflags`" }
     filter "action:vs*"
       links { "shlwapi" }
     filter {}