Index: share/mk/src.opts.mk
===================================================================
--- share/mk/src.opts.mk
+++ share/mk/src.opts.mk
@@ -199,6 +199,9 @@
     CLANG_EXTRAS \
     DTRACE_TESTS \
     EXPERIMENTAL \
+    GCC \
+    GCC_BOOTSTRAP \
+    GNUCXX \
     GNU_GREP_COMPAT \
     GPL_DTC \
     HESIOD \
@@ -297,24 +300,22 @@
 __DEFAULT_NO_OPTIONS+=LLVM_TARGET_BPF
 
 .include <bsd.compiler.mk>
-# If the compiler is not C++11 capable, disable Clang and use GCC instead.
-# This means that architectures that have GCC 4.2 as default can not
-# build Clang without using an external compiler.
+# If the compiler is not C++11 capable, disable Clang.  External toolchain will
+# be required.
 
 .if ${COMPILER_FEATURES:Mc++11} && (${__TT} != "mips" && \
     ${__TT} != "riscv" && ${__TT} != "sparc64")
 # Clang is enabled, and will be installed as the default /usr/bin/cc.
 __DEFAULT_YES_OPTIONS+=CLANG CLANG_BOOTSTRAP CLANG_IS_CC LLD
-__DEFAULT_NO_OPTIONS+=GCC GCC_BOOTSTRAP GNUCXX
 .elif ${COMPILER_FEATURES:Mc++11} && ${__T} != "sparc64"
 # If an external compiler that supports C++11 is used as ${CC} and Clang
-# supports the target, then Clang is enabled but GCC is installed as the
+# supports the target, then Clang is enabled but we still require an external
+# toolchain.
 # default /usr/bin/cc.
-__DEFAULT_YES_OPTIONS+=CLANG GCC GCC_BOOTSTRAP GNUCXX LLD
+__DEFAULT_YES_OPTIONS+=CLANG LLD
 __DEFAULT_NO_OPTIONS+=CLANG_BOOTSTRAP CLANG_IS_CC
 .else
 # Everything else disables Clang, and uses GCC instead.
-__DEFAULT_YES_OPTIONS+=GCC GCC_BOOTSTRAP GNUCXX
 __DEFAULT_NO_OPTIONS+=CLANG CLANG_BOOTSTRAP CLANG_IS_CC LLD
 .endif
 # In-tree binutils/gcc are older versions without modern architecture support.