diff --git a/scripts/makefile.mingw b/scripts/makefile.mingw
index f01c707a..04abcc12 100644
--- a/scripts/makefile.mingw
+++ b/scripts/makefile.mingw
@@ -14,6 +14,10 @@
 
 # Built from makefile.cygwin
 
+# This makefile expects to be run under the MSYS shell (part of
+# the MINGW project) and not under CMD.EXE which does not provide
+# "cat" or "sed".
+
 # This makefile intends to support building outside the src directory
 # if desired. When invoking it, specify an argument to SRCDIR on the
 # command line that points to the top of the directory where your source
@@ -77,7 +81,7 @@ CFLAGS= $(strip $(MINGW_CCFLAGS) $(addprefix -I,$(ZLIBINC)) \
 LIBNAME = libpng12
 PNGMAJ = 0
 MINGDLL = 12
-PNGMIN = 1.2.43rc01
+PNGMIN = 1.2.43rc02
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 SHAREDLIB=libpng$(MINGDLL).dll