--- a/PKGBUILD	2018-03-22 09:21:46.483009873 +0100
+++ b/PKGBUILD	2018-03-22 09:24:13.162273004 +0100
@@ -5,7 +5,8 @@
 # toolchain build order: linux-api-headers->glibc->binutils->gcc->binutils->glibc
 # NOTE: libtool requires rebuilt with each new gcc version
 
-pkgname=(gcc gcc-libs gcc-fortran gcc-objc gcc-ada gcc-go lib32-gcc-libs)
+pkgname=(gcc gcc-libs gcc-fortran)
+[ "x@MULTILIB@" == "xdisable" ] || pkgname+=(lib32-gcc-libs)
 pkgver=7.3.1+20180312
 _majorver=${pkgver:0:1}
 _islver=0.18
@@ -14,7 +15,8 @@ pkgdesc='The GNU Compiler Collection'
 arch=(x86_64)
 license=(GPL LGPL FDL custom)
 url='http://gcc.gnu.org'
-makedepends=(binutils libmpc gcc-ada doxygen lib32-glibc lib32-gcc-libs python)
+makedepends=(binutils libmpc doxygen python)
+[ "x@MULTILIB@" == "xdisable" ] || makedepends+=(lib32-glibc lib32-gcc-libs)
 checkdepends=(dejagnu inetutils)
 options=(!emptydirs)
 source=(https://sources.archlinux.org/other/gcc/gcc-${pkgver/+/-}.tar.xz{,.sig}
@@ -88,10 +90,10 @@ build() {
       --mandir=/usr/share/man \
       --infodir=/usr/share/info \
       --with-bugurl=https://bugs.archlinux.org/ \
-      --enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ \
+      --enable-languages=c,c++,fortran,lto \
       --enable-shared \
       --enable-threads=posix \
-      --enable-libmpx \
+      --disable-libmpx \
       --with-system-zlib \
       --with-isl \
       --enable-__cxa_atexit \
@@ -106,7 +108,7 @@ build() {
       --enable-install-libiberty \
       --with-linker-hash-style=gnu \
       --enable-gnu-indirect-function \
-      --enable-multilib \
+      --@MULTILIB@-multilib \
       --disable-werror \
       --enable-checking=release \
       --enable-default-pie \
@@ -139,25 +141,17 @@ package_gcc-libs() {
   rm -f "$pkgdir/$_libdir/libgcc_eh.a"
 
   for lib in libatomic \
-             libcilkrts \
              libgfortran \
-             libgo \
              libgomp \
-             libitm \
              libquadmath \
-             libsanitizer/{a,l,ub,t}san \
-             libstdc++-v3/src \
-             libvtv; do
+             libstdc++-v3/src; do
     make -C $CHOST/$lib DESTDIR="$pkgdir" install-toolexeclibLTLIBRARIES
   done
 
-  make -C $CHOST/libobjc DESTDIR="$pkgdir" install-libs
   make -C $CHOST/libstdc++-v3/po DESTDIR="$pkgdir" install
-  make -C $CHOST/libmpx DESTDIR="$pkgdir" install
   rm -f "$pkgdir/usr/lib/libmpx.spec"
 
   for lib in libgomp \
-             libitm \
              libquadmath; do
     make -C $CHOST/$lib DESTDIR="$pkgdir" install-info
   done
@@ -172,7 +166,7 @@ package_gcc-libs() {
 
 package_gcc() {
   pkgdesc="The GNU Compiler Collection - C and C++ frontends"
-  depends=("gcc-libs=$pkgver-$pkgrel" 'binutils>=2.28' libmpc)
+  depends=("gcc-libs" 'binutils>=2.28' libmpc)
   groups=('base-devel')
   optdepends=('lib32-gcc-libs: for generating code for 32-bit ABI')
   provides=($pkgname-multilib)
@@ -188,22 +182,22 @@ package_gcc() {
   install -m755 -t "$pkgdir/${_libdir}/" gcc/{cc1,cc1plus,collect2,lto1}
 
   make -C $CHOST/libgcc DESTDIR="$pkgdir" install
-  make -C $CHOST/32/libgcc DESTDIR="$pkgdir" install
+  [ "x@MULTILIB@" == "xdisable" ] || make -C $CHOST/32/libgcc DESTDIR="$pkgdir" install
   rm -f "$pkgdir"/usr/lib{,32}/libgcc_s.so*
 
   make -C $CHOST/libstdc++-v3/src DESTDIR="$pkgdir" install
   make -C $CHOST/libstdc++-v3/include DESTDIR="$pkgdir" install
   make -C $CHOST/libstdc++-v3/libsupc++ DESTDIR="$pkgdir" install
   make -C $CHOST/libstdc++-v3/python DESTDIR="$pkgdir" install
-  make -C $CHOST/32/libstdc++-v3/src DESTDIR="$pkgdir" install
-  make -C $CHOST/32/libstdc++-v3/include DESTDIR="$pkgdir" install
-  make -C $CHOST/32/libstdc++-v3/libsupc++ DESTDIR="$pkgdir" install
+  [ "x@MULTILIB@" == "xdisable" ] || make -C $CHOST/32/libstdc++-v3/src DESTDIR="$pkgdir" install
+  [ "x@MULTILIB@" == "xdisable" ] || make -C $CHOST/32/libstdc++-v3/include DESTDIR="$pkgdir" install
+  [ "x@MULTILIB@" == "xdisable" ] || make -C $CHOST/32/libstdc++-v3/libsupc++ DESTDIR="$pkgdir" install
 
   make DESTDIR="$pkgdir" install-libcc1
   install -d "$pkgdir/usr/share/gdb/auto-load/usr/lib"
   mv "$pkgdir"/usr/lib/libstdc++.so.6.*-gdb.py \
     "$pkgdir/usr/share/gdb/auto-load/usr/lib/"
-  rm "$pkgdir"/usr/lib{,32}/libstdc++.so*
+  rm -f "$pkgdir"/usr/lib{,32}/libstdc++.so*
 
   make DESTDIR="$pkgdir" install-fixincludes
   make -C gcc DESTDIR="$pkgdir" install-mkheaders
@@ -213,26 +207,16 @@ package_gcc() {
   ln -s /${_libdir}/liblto_plugin.so \
     "$pkgdir/usr/lib/bfd-plugins/"
 
-  make -C $CHOST/libcilkrts DESTDIR="$pkgdir" install-nodist_{toolexeclib,cilkinclude}HEADERS
   make -C $CHOST/libgomp DESTDIR="$pkgdir" install-nodist_{libsubinclude,toolexeclib}HEADERS
-  make -C $CHOST/libitm DESTDIR="$pkgdir" install-nodist_toolexeclibHEADERS
   make -C $CHOST/libquadmath DESTDIR="$pkgdir" install-nodist_libsubincludeHEADERS
-  make -C $CHOST/libsanitizer DESTDIR="$pkgdir" install-nodist_{saninclude,toolexeclib}HEADERS
-  make -C $CHOST/libsanitizer/asan DESTDIR="$pkgdir" install-nodist_toolexeclibHEADERS
-  make -C $CHOST/libmpx DESTDIR="$pkgdir" install-nodist_toolexeclibHEADERS
-  make -C $CHOST/32/libcilkrts DESTDIR="$pkgdir" install-nodist_toolexeclibHEADERS
-  make -C $CHOST/32/libgomp DESTDIR="$pkgdir" install-nodist_toolexeclibHEADERS
-  make -C $CHOST/32/libitm DESTDIR="$pkgdir" install-nodist_toolexeclibHEADERS
-  make -C $CHOST/32/libsanitizer DESTDIR="$pkgdir" install-nodist_{saninclude,toolexeclib}HEADERS
-  make -C $CHOST/32/libsanitizer/asan DESTDIR="$pkgdir" install-nodist_toolexeclibHEADERS
-  make -C $CHOST/32/libmpx DESTDIR="$pkgdir" install-nodist_toolexeclibHEADERS
+  [ "x@MULTILIB@" == "xdisable" ] || make -C $CHOST/32/libgomp DESTDIR="$pkgdir" install-nodist_toolexeclibHEADERS
 
   make -C libiberty DESTDIR="$pkgdir" install
   install -m644 libiberty/pic/libiberty.a "$pkgdir/usr/lib"
 
   make -C gcc DESTDIR="$pkgdir" install-man install-info
-  rm "$pkgdir"/usr/share/man/man1/{gccgo,gfortran}.1
-  rm "$pkgdir"/usr/share/info/{gccgo,gfortran,gnat-style,gnat_rm,gnat_ugn}.info
+  rm -f "$pkgdir"/usr/share/man/man1/{gccgo,gfortran}.1
+  rm -f "$pkgdir"/usr/share/info/{gccgo,gfortran,gnat-style,gnat_rm,gnat_ugn}.info
 
   make -C libcpp DESTDIR="$pkgdir" install
   make -C gcc DESTDIR="$pkgdir" install-po
@@ -262,14 +246,14 @@ package_gcc() {
 
 package_gcc-fortran() {
   pkgdesc='Fortran front-end for GCC'
-  depends=("gcc=$pkgver-$pkgrel")
+  depends=("gcc")
   provides=($pkgname-multilib)
   replaces=($pkgname-multilib)
 
   cd gcc-build
   make -C $CHOST/libgfortran DESTDIR="$pkgdir" install-cafexeclibLTLIBRARIES \
     install-{toolexeclibDATA,nodist_fincludeHEADERS}
-  make -C $CHOST/32/libgfortran DESTDIR=$pkgdir install-cafexeclibLTLIBRARIES \
+  [ "x@MULTILIB@" == "xdisable" ] || make -C $CHOST/32/libgfortran DESTDIR=$pkgdir install-cafexeclibLTLIBRARIES \
     install-{toolexeclibDATA,nodist_fincludeHEADERS}
   make -C $CHOST/libgomp DESTDIR="$pkgdir" install-nodist_fincludeHEADERS
   make -C gcc DESTDIR="$pkgdir" fortran.install-{common,man,info}