[linux] Allow a sysroot to be specified via SYSROOT=...
The cross-compiler will typically use the appropriate sysroot
directory automatically. This may not work for toolchains where a
single cross-compiler is used to produce output for multiple CPU
variants (e.g. 32-bit and 64-bit RISC-V).
Add a SYSROOT=... parameter that may be used to specify the relevant
sysroot directory, e.g.
make CROSS=riscv64-linux-gnu- SYSROOT=/usr/riscv32-linux-gnu/sys-root \
bin-riscv32-linux/tests.linux
Signed-off-by: Michael Brown <mcb30@ipxe.org>
diff --git a/src/Makefile.linux b/src/Makefile.linux
index b278c8c..762437a 100644
--- a/src/Makefile.linux
+++ b/src/Makefile.linux
@@ -29,6 +29,9 @@
# Compiler flags for building host API wrapper
#
LINUX_CFLAGS += -Os -idirafter include -DSYMBOL_PREFIX=$(SYMBOL_PREFIX)
+ifneq ($(SYSROOT),)
+LINUX_CFLAGS += --sysroot=$(SYSROOT)
+endif
# Check for libslirp
#
