[makeotfexe] hotconv featgram.c Xcode compiler: many errors from unnecessary parens in featgram.c

[readroberts]

The -Wparentheses-equality warning is useful for more than just extra parens, and I'd like to keep it. Solved the problem by fixing the source code in featgram.c. A short -term solution: I replaced all occurrences of "(if|while) (\s+(LA(1)==([^)]+))\s*)" with " \1 (LA(1)==\2)". Short-term because this will have to be repeated every time someone regenerates the featgram.c file by running the ANTLR parser. Needs to eventually be fixed in the ANTLR parser itself.