README,manibuilder: Update environment overrides for DJGPP

The currently documented DJGPP setup doesn't utilize pkg-config, hence
we have to specify the presence of libpci explicitly.

Change-Id: I1e5cc9e0235fd49948edd9d39087735b8685638e
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/73776
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/util/manibuilder/Makefile.env b/util/manibuilder/Makefile.env
index 6a352f3..79bca73 100644
--- a/util/manibuilder/Makefile.env
+++ b/util/manibuilder/Makefile.env
@@ -5,7 +5,8 @@
 djgpp\:6.1.0: CC=ccache i586-pc-msdosdjgpp-gcc
 djgpp\:6.1.0: STRIP=i586-pc-msdosdjgpp-strip
 djgpp\:6.1.0: LIBS_BASE=../
-djgpp\:6.1.0: MAKEARGS+=strip CONFIG_JLINK_SPI=no
+djgpp\:6.1.0: MAKEARGS+=HAS_LIBPCI=yes CONFIG_LIBPCI_LDFLAGS=-lpci
+djgpp\:6.1.0: MAKEARGS+=strip
 
 # Compiler doesn't like simplified initializers, e.g. `= { 0 };`
 $(filter centos\:%, $(MULTIARCH_TAGS)): MAKEARGS+=WARNERROR=no