File fix-png.patch of Package lincity

diff -Nur lincity-1.13.1/configure.ac lincity-new/configure.ac
--- lincity-1.13.1/configure.ac	2004-06-27 05:49:00.000000000 +0200
+++ lincity-new/configure.ac	2018-08-08 23:51:08.374536066 +0200
@@ -15,6 +15,10 @@
 AC_PROG_MAKE_SET
 AC_PROG_LIBTOOL
 
+AC_SUBST([PNG_CFLAGS])
+AC_SUBST([PNG_LIBS])
+PKG_CHECK_MODULES([PNG], [libpng16])
+
 dnl Autodetect presence of gzip
 if eval "test x$with_gzip = x"; then
   AC_CHECK_PROG(with_gzip,gzip,"yes")
diff -Nur lincity-1.13.1/Makefile.am lincity-new/Makefile.am
--- lincity-1.13.1/Makefile.am	2004-07-03 10:26:12.000000000 +0200
+++ lincity-new/Makefile.am	2018-08-09 00:07:22.556154760 +0200
@@ -171,18 +171,19 @@
 
 liblcx_la_SHORTNAME = lcx
 liblcx_la_SOURCES = $(gui_SOURCES) lcx11.c 
-liblcx_la_LIBADD = @X_LIBS@ -lXext -lX11 -lpng -lz -lm
+liblcx_la_LIBADD = @X_LIBS@ -lXext -lX11 $(PNG_LIBS) -lz -lm
 liblcx_la_CPPFLAGS = $(X_DEFS)
 
 liblcsvga_la_SHORTNAME = lcsvga
 liblcsvga_la_SOURCES = $(gui_SOURCES) lcsvga.c
-liblcsvga_la_LIBADD = @SVGA_LIBS@ -lvgagl -lvga -lpng -lz -lm
+liblcsvga_la_LIBADD = @SVGA_LIBS@ -lvgagl -lvga $(PNG_LIBS) -lz -lm
 liblcsvga_la_CPPFLAGS = $(SVGA_DEFS)
 
 
 lincity_SOURCES = $(engine_SOURCES)
 lincity_DEPENDENCIES = LCSVGA_LIBS modules/libmodules.la
 lincity_LDADD = liblcsvga.la modules/libmodules.la
+CFLAGS += $(PNG_CFLAGS)
 
 xlincity_SOURCES = $(engine_SOURCES)
 xlincity_DEPENDENCIES = LCX_LIBS modules/libmodules.la