The shell builtin 'source' command is a bash extension.
Use the '.' portable command.

This fix building when /bin/sh is dash (Ubuntu 16):

  $ make -C roms efi
  [...]
  Fd File Name:QEMU_EFI
  (/source/qemu/roms/edk2/Build/ArmVirtQemu-AARCH64/DEBUG_GCC5/FV/QEMU_EFI.fd)
  Fd File Name:QEMU_VARS
  (/source/qemu/roms/edk2/Build/ArmVirtQemu-AARCH64/DEBUG_GCC5/FV/QEMU_VARS.fd)
  GUID cross reference file can be found at
  /source/qemu/roms/edk2/Build/ArmVirtQemu-AARCH64/DEBUG_GCC5/FV/Guid.xref
  - Done -
  Build end time: 16:33:29, Mar.09 2019
  Build total time: 00:03:35
  cp edk2/Build/ArmVirtQemu-AARCH64/DEBUG_/FV/QEMU_EFI.fd \
  	../pc-bios/edk2-aarch64-code.fd
  cp: cannot stat 'edk2/Build/ArmVirtQemu-AARCH64/DEBUG_/FV/QEMU_EFI.fd':
  No such file or directory
  Makefile.edk2:45: recipe for target '../pc-bios/edk2-aarch64-code.fd' failed
  make[1]: *** [../pc-bios/edk2-aarch64-code.fd] Error 1
  make[1]: Leaving directory '/source/qemu/roms'
  Makefile:148: recipe for target 'efi' failed
  make: *** [efi] Error 2
  make: Leaving directory '/source/qemu/roms'

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 roms/Makefile.edk2 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/roms/Makefile.edk2 b/roms/Makefile.edk2
index ad6fff044c..6c5e9b9eea 100644
--- a/roms/Makefile.edk2
+++ b/roms/Makefile.edk2
@@ -11,7 +11,7 @@
 # THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
 # WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 
-toolchain = $(shell source ./edk2-funcs.sh && qemu_edk2_get_toolchain $(1))
+toolchain = $(shell . ./edk2-funcs.sh && qemu_edk2_get_toolchain $(1))
 
 licenses := \
 	edk2/License.txt \
-- 
2.20.1