Fix unneeded recompiles of glslang_tab.cpp

To work around qmake deficiencies src/angle/src/compiler/translator.pro
contains a no-op extra compiler that "creates" glslang_tab.cpp and adds
a dependency to glslang_tab.h.

However, both files are created in one bison call, and for some reason
the .cpp file is created before the .h file. Then the dependency
glslang_tab.cpp -> glslang_tab.h results in recompiling glslang_tab.cpp
on every incremental build.

Ensure that glslang_tab.cpp is newer than glslang_tab.h.

Change-Id: I6f59e213c84af85c59c02d90ac220bd347faddd1
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>

src/angle/src/compiler/translator.pro

@@ -189,7 +189,8 @@ QMAKE_EXTRA_COMPILERS += flex
 defineReplace(myDirName) { return($$dirname(1)) }
 bison.commands = $$addGnuPath(bison) --no-lines --skeleton=yacc.c --defines=${QMAKE_FILE_OUT} \
                 --output=${QMAKE_FUNC_FILE_OUT_myDirName}$$QMAKE_DIR_SEP${QMAKE_FILE_OUT_BASE}.cpp \
-                ${QMAKE_FILE_NAME}
+                ${QMAKE_FILE_NAME}$$escape_expand(\\n\\t) \
+                @echo // EOF>>${QMAKE_FUNC_FILE_OUT_myDirName}$$QMAKE_DIR_SEP${QMAKE_FILE_OUT_BASE}.cpp
 bison.output = $${BUILDSUBDIR}${QMAKE_FILE_BASE}_tab.h
 bison.input = BISON_SOURCES
 bison.dependency_type = TYPE_C