[libpng16] Mention cmake "PNG_HARDWARE_OPTIMIZATIONS" in INSTALL
diff --git a/INSTALL b/INSTALL
index 14497f6..1d6a352 100644
--- a/INSTALL
+++ b/INSTALL
@@ -319,6 +319,16 @@
CPPFLAGS += "-DPNG_ARM_NEON_OPT=0, -DPNG_MIPS_MSA_OPT=0,
-DPNG_INTEL_SSE_OPT=0, -DPNG_POWERPC_VSX_OPT=0"
+If you are using cmake, hardware optimizations are "on"
+by default. To disable them, use
+
+ cmake . -DPNG_ARM_NEON=no -DPNG_INTEL_SSE=no \
+ -DPNG_MIPS_MSA=no -DPNG_POWERPC_VSX=no
+
+or disable them all at once with
+
+ cmake . -DPNG_HARDWARE_OPTIMIZATIONS=no
+
XV. Changes to the build and configuration of libpng in libpng-1.5.x
Details of internal changes to the library code can be found in the CHANGES
