sys-firmware/iopmod: Add "modules +tools" USE flags

Modules are typically built with a cross-compiler, such as with

USE="modules -tools" mipsr5900el-unknown-linux-gnu-emerge -v sys-firmware/iopmod

The modules will then be installed in the directory
/usr/mipsr5900el-unknown-linux-gnu/lib/firmware/ps2

It's possible to cross-compile the tools as well, but then with

USE="modules tools static" mipsr5900el-unknown-linux-gnu-emerge -v sys-firmware/iopmod

where "static" is needed for the tools to run with QEMU during
building. A typical error would otherwise be

qemu-mipsel:    Could not open '/lib/ld.so.1': No such file or directory

Also, if the error

qemu-mipsel: unable to find CPU model 'R5900'

occurs, the app-emulation/qemu-mipsr5900el package needs to be
installed and "interpreter /usr/bin/qemu-mipsr5900el" set in
/proc/sys/fs/binfmt_misc/qemu-mipsel.

sys-firmware/iopmod/iopmod-9999.ebuild

@@ -1,5 +1,7 @@
 EAPI=7
 
+inherit toolchain-funcs
+
 DESCRIPTION="PlayStation 2 input/output processor (IOP) modules and tools"
 HOMEPAGE="https://github.com/frno7/iopmod"
 
@@ -17,7 +19,7 @@ fi
 
 LICENSE="GPL-2 MIT"
 SLOT="0"
-IUSE="static"
+IUSE="modules +tools static"
 
 RDEPEND=""
 DEPEND=""
@@ -34,11 +36,32 @@ src_compile() {
 
  use static && LDFLAGS+=" -static"
 
- emake LDFLAGS="${LDFLAGS}" V=1 tool || die
+ if use tools
+ then
+ emake CC="$(tc-getCC)" AR="$(tc-getAR)" \
+ LDFLAGS="${LDFLAGS}" V=1 tool || die
+ fi
+
+ if use modules
+ then
+ emake CC="$(tc-getBUILD_CC)" AR="$(tc-getBUILD_AR)" \
+ CCC="$(tc-getCC)" CLD="$(tc-getLD)" \
+ CFLAGS="-Wall -Iinclude" \
+ LDFLAGS="${LDFLAGS}" V=1 module || die
+ fi
 }
 
 src_install() {
- dobin tool/iopmod-info
- dobin tool/iopmod-link
- dobin tool/iopmod-symc
+ if use tools
+ then
+ dobin tool/iopmod-info
+ dobin tool/iopmod-link
+ dobin tool/iopmod-symc
+ fi
+
+ if use modules
+ then
+ insinto /lib/firmware/ps2
+ doins module/*.irx
+ fi
 }