[Bug jit/64708] libgccjit installed twice

["dmalcolm at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64708

--- Comment #1 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
[david@c64 install]$ ll $(find -name "libgccjit.so*")
-rwxr-xr-x. 1 david david 78637910 Jan 26 12:59
./libexec/gcc/x86_64-unknown-linux-gnu/5.0.0/libgccjit.so
lrwxrwxrwx. 1 david david       14 Jan 26 12:59 ./lib/libgccjit.so ->
libgccjit.so.0
lrwxrwxrwx. 1 david david       18 Jan 26 12:59 ./lib/libgccjit.so.0 ->
libgccjit.so.0.0.1
-rwxr-xr-x. 1 david david 78637910 Jan 26 12:59 ./lib/libgccjit.so.0.0.1


The libdir one is from gcc/jit/Make-lang.in:
jit.install-common: installdirs
    $(INSTALL_PROGRAM) $(LIBGCCJIT_FILENAME) \
      $(DESTDIR)/$(libdir)/$(LIBGCCJIT_FILENAME)
        (...snip...)


The libexec one is from gcc/Makefile.in:

# Install the compiler executables built during cross compilation.
install-common: native lang.install-common installdirs
    for file in $(COMPILERS); do \
      if [ -f $$file ] ; then \
        rm -f $(DESTDIR)$(libexecsubdir)/$$file; \
        $(INSTALL_PROGRAM) $$file $(DESTDIR)$(libexecsubdir)/$$file; \
      else true; \
      fi; \
    done
        (...snip...)

since COMPILERS contains "libgccjit.so".