[Buildroot] Make install-exec not working

[Alexandru Tudose]

I have compiled X11R7 packages on x86_64 system for x86 architecture,
but most of them haven't been installed in target directory, but they
appear in staging directory. I found that install-exec is not working
after modifying in Makefile.autotools.in:

$(2)_INSTALL_TARGET_OPT         ?= DESTDIR=$$(TARGET_DIR)  install-exec
to
$(2)_INSTALL_TARGET_OPT         ?= DESTDIR=$$(TARGET_DIR)  install.

Can someone confirm that it is a x86_64 bug?
As usual message: "fixed font not found", but it start after
installing font-misc-misc package.