Don't use NEON optimized code in lpng_v163

samples/fx_lpng/lpng_v163/pngpriv.h

 
 /* pngpriv.h - private declarations for use inside libpng
  *
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2013 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
  * Last changed in libpng 1.6.3 [July 18, 2013]
  *
@@ skipping 89 matching lines @@
  *
  * NOTE: symbol prefixing does not pass $(CFLAGS) to the preprocessor, because
  * this is not possible with certain compilers (Oracle SUN OS CC), as a result
  * it is necessary to ensure that all extern functions that *might* be used
  * regardless of $(CFLAGS) get declared in this file.  The test on __ARM_NEON__
  * below is one example of this behavior because it is controlled by the
  * presence or not of -mfpu=neon on the GCC command line, it is possible to do
  * this in $(CC), e.g. "CC=gcc -mfpu=neon", but people who build libpng rarely
  * do this.
  */
+/*
+ * pdfium: This version of libpng does not contain the arm neon optimized code
+ * so we should never try to reference it.
+ */
+#if 0
 #ifndef PNG_ARM_NEON_OPT
    /* ARM NEON optimizations are being controlled by the compiler settings,
     * typically the target FPU.  If the FPU has been set to NEON (-mfpu=neon
     * with GCC) then the compiler will define __ARM_NEON__ and we can rely
     * unconditionally on NEON instructions not crashing, otherwise we must
     * disable use of NEON instructions:
     */
 #  ifdef __ARM_NEON__
 #     define PNG_ARM_NEON_OPT 2
 #  else
 #     define PNG_ARM_NEON_OPT 0
 #  endif
 #endif
 
 #if PNG_ARM_NEON_OPT > 0
    /* NEON optimizations are to be at least considered by libpng, so enable the
     * callbacks to do this.
     */
 #  define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_neon
 #endif
+#endif
 
 /* Is this a build of a DLL where compilation of the object modules requires
  * different preprocessor settings to those required for a simple library?  If
  * so PNG_BUILD_DLL must be set.
  *
  * If libpng is used inside a DLL but that DLL does not export the libpng APIs
  * PNG_BUILD_DLL must not be set.  To avoid the code below kicking in build a
  * static library of libpng then link the DLL against that.
  */
 #ifndef PNG_BUILD_DLL
@@ skipping 1857 matching lines @@
 /* Maintainer: Put new private prototypes here ^ */
 
 #include "pngdebug.h"
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif /* PNG_VERSION_INFO_ONLY */
 #endif /* PNGPRIV_H */