Using backtrace() is of no use when building with PIE (which most
distro compilers do by default) and prevents catching the coredump
for later retracing, which is needed since distros usually don't
install debug symbols by default either.
This patch thus only enables backtrace() when --enable-maintainer-mode
is passed and also tries to explicitly disable PIE.
Check for HAVE_EXECINFO_H for all __iwd_backtrace_init usages.
Fixes:
src/main.o: In function `main':
main.c:(.text.startup+0x798): undefined reference to `__iwd_backtrace_init'
collect2: error: ld returned 1 exit status
