Fixing compiler warnings
When debugging a problem, gratuitous compiler warnings often get in the way by obscuring real problems.
This is why projects should try to eliminate them -- so that when a new one pops up, such as when new code is added, or the build is performed on a new platform -- the issue can attract its due attention.
The attached patch fixes warnings, that I observed compiling with ``-Wall -Werror'' on RHEL-5.4/x86_64 system. Please, consider merging these changes in.
The addressed problems are:
- rb_thread_join was not declared (intern.h) with the rest of the rb_thread functions. Private declarations existed in some C-files...
- The PUSH_FRAME duly defined the local variable _frame as volatile. However, when the value of _frame was assigned to the global ruby_frame, this qualifier was lost. There were as many warnings about this, as there are invocations of the PUSH_FRAME macro.
- The little thread_timer() function MUST be declared as returning void*, because it is passed to pthread_create(). Compiler warned, that a non-void function lacked the return-statement. I added one...
- regex.c in its error reporting tried to print ptrdiff_t value as int. On 64-bit platforms ptrdiff_t is, usually, long int, but that's an impossibly large value for a regular expression's length. Explicit casting of the pointer-difference down to int should be fine.
- parse.y defined an unused static function arg_prepend()
Also, when compiling with a recent gcc at optimization level -O2 (or higher), util.c throws a number of warnings about breaking strict-aliasing rules. There is no /easy/ fix for this, but the work-around is to simply compile that one file with -fno-strict-aliasing (or whatever flag is needed for this with non-gcc compilers). A /sample/ patch for this issue is attached separately.