Jordan Crouse submitted a patch to only include xregcomp.c when we actually
use it, thus fixing building against uClibc with regex support disabled.
diff --git a/libbb/Makefile.in b/libbb/Makefile.in
index ae9c9f0..f94c100 100644
--- a/libbb/Makefile.in
+++ b/libbb/Makefile.in
@@ -29,7 +29,7 @@
safe_strncpy.c setup_environment.c sha1.c simplify_path.c \
trim.c u_signal_names.c vdprintf.c verror_msg.c \
vherror_msg.c vperror_msg.c wfopen.c xconnect.c xgetcwd.c xstat.c \
- xgethostbyname.c xgethostbyname2.c xreadlink.c xregcomp.c xgetlarg.c \
+ xgethostbyname.c xgethostbyname2.c xreadlink.c xgetlarg.c \
get_terminal_width_height.c fclose_nonstdin.c fflush_stdout_and_exit.c \
getopt_ulflags.c default_error_retval.c wfopen_input.c speed_table.c \
perror_nomsg_and_die.c perror_nomsg.c skip_whitespace.c bb_askpass.c \
@@ -49,6 +49,20 @@
LIBBB-$(CONFIG_DF)+= find_mount_point.c
LIBBB-$(CONFIG_EJECT)+= find_mount_point.c
+# We shouldn't build xregcomp.c if we don't need it - this ensures we don't
+# require regex.h to be in the include dir even if we don't need it thereby
+# allowing us to build busybox even if uclibc regex support is disabled.
+
+regex-y:=
+
+regex-$(CONFIG_AWK) += xregcomp.c
+regex-$(CONFIG_SED) += xregcomp.c
+regex-$(CONFIG_LESS) += xregcomp.c
+regex-$(CONFIG_DEVFSD) += xregcomp.c
+
+# Sort has the happy side efect of returning a unique list
+LIBBB-y += $(sort $(regex-y))
+
LIBBB-y:=$(patsubst %,$(srcdir)/%,$(LIBBB-y))
get-file-subparts = $(addsuffix .o,$(shell sed -n -e "s/^\#ifdef L_//p" ${1}))