8080695: splashscreen_png.c compile error with gcc 4.9.2
Summary: mark locals volatile to silence gcc arround longjmp
Reviewed-by: azvegint, serb
^build/
^dist/
^webrev
/nbproject/private/
^src/share/tools/hsdis/build/
^src/share/tools/IdealGraphVisualizer/[a-zA-Z0-9]*/build/
^src/share/tools/IdealGraphVisualizer/build/
^src/share/tools/IdealGraphVisualizer/dist/
^src/share/tools/IdealGraphVisualizer/nbplatform/
.igv.log
^.hgtip
.DS_Store