Check libpng directly into third_party/

third_party/libpng/scripts/pnglibconf.mak

Index: third_party/libpng/scripts/pnglibconf.mak
diff --git a/third_party/libpng/scripts/pnglibconf.mak b/third_party/libpng/scripts/pnglibconf.mak
new file mode 100755
index 0000000000000000000000000000000000000000..c125ca2c977808e65a475a56b7359cc5677acc0b
--- /dev/null
+++ b/third_party/libpng/scripts/pnglibconf.mak
@@ -0,0 +1,55 @@
+#!/usr/bin/make -f
+# pnglibconf.mak - standard make lines for pnglibconf.h
+#
+# These lines are copied from Makefile.am, they illustrate
+# how to automate the build of pnglibconf.h from scripts/pnglibconf.dfa
+# given just 'awk', a C preprocessor and standard command line utilities
+
+# Override as appropriate, these definitions can be overridden on
+# the make command line (AWK='nawk' for example).
+AWK = gawk
+AWK = mawk
+AWK = nawk
+AWK = one-true-awk
+AWK = awk  # Crashes on SunOS 5.10 - use 'nawk'
+CPP = $(CC) -E # On SUN OS 5.10 if this causes problems use /lib/cpp
+
+MOVE = mv
+DELETE = rm -f
+ECHO = echo
+DFA_XTRA = # Put your configuration file here, see scripts/pnglibconf.dfa.  Eg:
+# DFA_XTRA = pngusr.dfa
+
+# CPPFLAGS should contain the options to control the result,
+# but DEFS and CFLAGS are also supported here, override
+# as appropriate
+DFNFLAGS = $(DEFS) $(CPPFLAGS) $(CFLAGS)
+
+# srcdir is a defacto standard for the location of the source
+srcdir = .
+
+# The standard pnglibconf.h exists as scripts/pnglibconf.h.prebuilt,
+# copy this if the following doesn't work.
+pnglibconf.h: pnglibconf.dfn
+	$(DELETE) $@ pnglibconf.c pnglibconf.out pnglibconf.tmp
+	$(ECHO) '#include "pnglibconf.dfn"' >pnglibconf.c
+	$(ECHO) "If '$(CC) -E' crashes try /lib/cpp (e.g. CPP='/lib/cpp')" >&2
+	$(CPP) $(DFNFLAGS) pnglibconf.c >pnglibconf.out
+	$(AWK) -f "$(srcdir)/scripts/dfn.awk" out="pnglibconf.tmp" pnglibconf.out 1>&2
+	$(MOVE) pnglibconf.tmp $@
+
+pnglibconf.dfn: $(srcdir)/scripts/pnglibconf.dfa $(srcdir)/scripts/options.awk $(srcdir)/pngconf.h $(srcdir)/pngusr.dfa $(DFA_XTRA)
+	$(DELETE) $@ pnglibconf.pre pnglibconf.tmp
+	$(ECHO) "Calling $(AWK) from scripts/pnglibconf.mak" >&2
+	$(ECHO) "If 'awk' crashes try a better awk (e.g. AWK='nawk')" >&2
+	$(AWK) -f $(srcdir)/scripts/options.awk out="pnglibconf.pre"\
+	    version=search $(srcdir)/pngconf.h $(srcdir)/scripts/pnglibconf.dfa\
+	    $(srcdir)/pngusr.dfa $(DFA_XTRA) 1>&2
+	$(AWK) -f $(srcdir)/scripts/options.awk out="pnglibconf.tmp" pnglibconf.pre 1>&2
+	$(MOVE) pnglibconf.tmp $@
+
+clean-pnglibconf:
+	$(DELETE) pnglibconf.h pnglibconf.c pnglibconf.out pnglibconf.pre \
+	pnglibconf.dfn
+
+clean: clean-pnglibconf