Nuke extern libz as mingw-64 packs in a libz and it causes issues with libpng

extern/for_mingw/lib/libpng.la

@@ -17,7 +17,7 @@ old_library='libpng16.a'
 inherited_linker_flags=''
 
 # Libraries that this one depends upon.
-dependency_libs=' -L/home/roothorick/stepmania/extern/for_mingw/lib -lz'
+dependency_libs=' -lz'
 
 # Names of additional weak libraries provided by this library
 weak_library_names=''

extern/for_mingw/lib/libpng16.la

@@ -17,7 +17,7 @@ old_library='libpng16.a'
 inherited_linker_flags=''
 
 # Libraries that this one depends upon.
-dependency_libs=' -L/home/roothorick/stepmania/extern/for_mingw/lib -lz'
+dependency_libs=' -lz'
 
 # Names of additional weak libraries provided by this library
 weak_library_names=''

extern/for_mingw/lib/pkgconfig/zlib.pc

@@ -1,13 +0,0 @@
-prefix=/usr/local
-exec_prefix=/usr/local
-libdir=lib
-sharedlibdir=lib
-includedir=include
-
-Name: zlib
-Description: zlib compression library
-Version: 1.2.8
-
-Requires:
-Libs: -L${libdir} -L${sharedlibdir} -lz
-Cflags: -I${includedir}