Update to libpng 1.2.52 (rollup change only)

third_party/libpng/pnggccrd.c

-/* pnggccrd.c was removed from libpng-1.2.20. */
-
-/* This code snippet is for use by configure's compilation test. */
+/* pnggccrd.c
+ *
+ * Last changed in libpng 1.2.48 [March 8, 2012]
+ * Copyright (c) 1998-2012 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This code snippet is for use by configure's compilation test. Most of the
+ * remainder of the file was removed from libpng-1.2.20, and all of the
+ * assembler code was removed from libpng-1.2.48.
+ */
 
 #if (!defined _MSC_VER) && \
     defined(PNG_ASSEMBLER_CODE_SUPPORTED) && \
     defined(PNG_MMX_CODE_SUPPORTED)
 
 int PNGAPI png_dummy_mmx_support(void);
 
-static int _mmx_supported = 2; // 0: no MMX; 1: MMX supported; 2: not tested
-
-int PNGAPI
-png_dummy_mmx_support(void) __attribute__((noinline));
-
-int PNGAPI
-png_dummy_mmx_support(void)
+int PNGAPI png_dummy_mmx_support(void)
 {
-   int result;
-#ifdef PNG_MMX_CODE_SUPPORTED  // superfluous, but what the heck
-    __asm__ __volatile__ (
-#ifdef __x86_64__
-        "pushq %%rbx          \n\t"  // rbx gets clobbered by CPUID instruction
-        "pushq %%rcx          \n\t"  // so does rcx...
-        "pushq %%rdx          \n\t"  // ...and rdx (but rcx & rdx safe on Linux)
-        "pushfq               \n\t"  // save Eflag to stack
-        "popq %%rax           \n\t"  // get Eflag from stack into rax
-        "movq %%rax, %%rcx    \n\t"  // make another copy of Eflag in rcx
-        "xorl $0x200000, %%eax \n\t" // toggle ID bit in Eflag (i.e., bit 21)
-        "pushq %%rax          \n\t"  // save modified Eflag back to stack
-        "popfq                \n\t"  // restore modified value to Eflag reg
-        "pushfq               \n\t"  // save Eflag to stack
-        "popq %%rax           \n\t"  // get Eflag from stack
-        "pushq %%rcx          \n\t"  // save original Eflag to stack
-        "popfq                \n\t"  // restore original Eflag
-#else
-        "pushl %%ebx          \n\t"  // ebx gets clobbered by CPUID instruction
-        "pushl %%ecx          \n\t"  // so does ecx...
-        "pushl %%edx          \n\t"  // ...and edx (but ecx & edx safe on Linux)
-        "pushfl               \n\t"  // save Eflag to stack
-        "popl %%eax           \n\t"  // get Eflag from stack into eax
-        "movl %%eax, %%ecx    \n\t"  // make another copy of Eflag in ecx
-        "xorl $0x200000, %%eax \n\t" // toggle ID bit in Eflag (i.e., bit 21)
-        "pushl %%eax          \n\t"  // save modified Eflag back to stack
-        "popfl                \n\t"  // restore modified value to Eflag reg
-        "pushfl               \n\t"  // save Eflag to stack
-        "popl %%eax           \n\t"  // get Eflag from stack
-        "pushl %%ecx          \n\t"  // save original Eflag to stack
-        "popfl                \n\t"  // restore original Eflag
-#endif
-        "xorl %%ecx, %%eax    \n\t"  // compare new Eflag with original Eflag
-        "jz 0f                \n\t"  // if same, CPUID instr. is not supported
-
-        "xorl %%eax, %%eax    \n\t"  // set eax to zero
-//      ".byte  0x0f, 0xa2    \n\t"  // CPUID instruction (two-byte opcode)
-        "cpuid                \n\t"  // get the CPU identification info
-        "cmpl $1, %%eax       \n\t"  // make sure eax return non-zero value
-        "jl 0f                \n\t"  // if eax is zero, MMX is not supported
-
-        "xorl %%eax, %%eax    \n\t"  // set eax to zero and...
-        "incl %%eax           \n\t"  // ...increment eax to 1.  This pair is
-                                     // faster than the instruction "mov eax, 1"
-        "cpuid                \n\t"  // get the CPU identification info again
-        "andl $0x800000, %%edx \n\t" // mask out all bits but MMX bit (23)
-        "cmpl $0, %%edx       \n\t"  // 0 = MMX not supported
-        "jz 0f                \n\t"  // non-zero = yes, MMX IS supported
-
-        "movl $1, %%eax       \n\t"  // set return value to 1
-        "jmp  1f              \n\t"  // DONE:  have MMX support
-
-    "0:                       \n\t"  // .NOT_SUPPORTED: target label for jump instructions
-        "movl $0, %%eax       \n\t"  // set return value to 0
-    "1:                       \n\t"  // .RETURN: target label for jump instructions
-#ifdef __x86_64__
-        "popq %%rdx           \n\t"  // restore rdx
-        "popq %%rcx           \n\t"  // restore rcx
-        "popq %%rbx           \n\t"  // restore rbx
-#else
-        "popl %%edx           \n\t"  // restore edx
-        "popl %%ecx           \n\t"  // restore ecx
-        "popl %%ebx           \n\t"  // restore ebx
-#endif
-
-//      "ret                  \n\t"  // DONE:  no MMX support
-                                     // (fall through to standard C "ret")
-
-        : "=a" (result)              // output list
-
-        :                            // any variables used on input (none)
-
-                                     // no clobber list
-//      , "%ebx", "%ecx", "%edx"     // GRR:  we handle these manually
-//      , "memory"   // if write to a variable gcc thought was in a reg
-//      , "cc"       // "condition codes" (flag bits)
-    );
-    _mmx_supported = result;
-#else
-    _mmx_supported = 0;
-#endif /* PNG_MMX_CODE_SUPPORTED */
-
-    return _mmx_supported;
+     /* 0: no MMX; 1: MMX supported; 2: not tested */
+     return 2;
 }
 #endif