Index: lib/clang/clang.lib.mk
===================================================================
--- lib/clang/clang.lib.mk
+++ lib/clang/clang.lib.mk
@@ -6,4 +6,8 @@
 
 INTERNALLIB=
 
+.if ${MACHINE_CPUARCH} == "arm"
+STATIC_CXXFLAGS+= -mlong-calls
+.endif
+
 .include <bsd.lib.mk>
Index: lib/libc++/Makefile
===================================================================
--- lib/libc++/Makefile
+++ lib/libc++/Makefile
@@ -6,6 +6,9 @@
 HDRDIR=		${.CURDIR}/../../contrib/libc++/include
 SRCDIR=		${.CURDIR}/../../contrib/libc++/src
 CXXINCLUDEDIR=	${INCLUDEDIR}/c++/v${SHLIB_MAJOR}
+.if ${MACHINE_CPUARCH} == "arm"
+STATIC_CXXFLAGS+= -mlong-calls
+.endif
 
 .PATH: ${SRCDIR}
 
Index: usr.bin/clang/clang/Makefile
===================================================================
--- usr.bin/clang/clang/Makefile
+++ usr.bin/clang/clang/Makefile
@@ -11,6 +11,10 @@
 
 .if ${MK_SHARED_TOOLCHAIN} == "no"
 NO_SHARED?= yes
+
+.if ${MACHINE_CPUARCH} == "arm"
+CFLAGS+= -mlong-calls
+.endif
 .endif
 
 LINKS=	${BINDIR}/clang ${BINDIR}/clang++ \
Index: usr.bin/clang/lldb/Makefile
===================================================================
--- usr.bin/clang/lldb/Makefile
+++ usr.bin/clang/lldb/Makefile
@@ -8,6 +8,9 @@
 
 CFLAGS+=	-I${LLDB_SRCS}/include
 CXXFLAGS+=	-std=c++11
+.if ${MACHINE_CPUARCH} == "arm"
+CFLAGS+=	-mlong-calls
+.endif
 
 SRCDIR=	tools/lldb/tools/driver
 SRCS=	Driver.cpp \