[Buildroot] [PATCH next v2 1/2] package/apr-util: fix build with per-package folders

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

With per-package folder support enable, the build of apr-util fails,
for two reasons:

 - The rules.mk file is generated by the 'apr' package, and then
   copied into the 'apr-util' source directory. This is done by the
   'apr-util' build process. Unfortunately, this rules.mk file has a
   number of hardcoded paths: to the compiler and to the libtool
   script.

   Due to this, the compiler from the 'apr' per-package folder gets
   used. But this compiler uses the 'apr' package sysroot, which does
   not have all the dependencies of the 'apr-util' package, causing
   the build to fail because <expat.h> is not found.

 - Similarly, the libtool script itself has some hardcoded paths,
   which make it use the compiler/linker from the 'apr' per-package
   folder, so it does not find the expat library.

We fix both issues by doing the necessary replacement in both rules.mk
and libtool.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
---
Changes since v1:
 - Drop the useless logic to copy the libtool script before doing the
   replacement: as noted by Yann E. Morin, sed is properly breaking
   hardlinks when doing an in-place replacement.
---
 package/apr-util/apr-util.mk | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/package/apr-util/apr-util.mk b/package/apr-util/apr-util.mk
index b006964ccb..379dfa692e 100644
--- a/package/apr-util/apr-util.mk
+++ b/package/apr-util/apr-util.mk
@@ -15,6 +15,13 @@ APR_UTIL_CONF_OPTS = \
 	--with-apr=$(STAGING_DIR)/usr/bin/apr-1-config
 APR_UTIL_CONFIG_SCRIPTS = apu-1-config
 
+define APR_UTIL_FIX_RULES_MK_LIBTOOL
+	$(SED) 's,$(PER_PACKAGE_DIR)/apr/,$(PER_PACKAGE_DIR)/apr-util/,g' $(@D)/build/rules.mk
+	$(SED) 's,$(PER_PACKAGE_DIR)/apr/,$(PER_PACKAGE_DIR)/apr-util/,g' \
+		$(STAGING_DIR)/usr/build-1/libtool
+endef
+APR_UTIL_POST_CONFIGURE_HOOKS += APR_UTIL_FIX_RULES_MK_LIBTOOL
+
 # When iconv is available, then use it to provide charset conversion
 # features.
 APR_UTIL_DEPENDENCIES += $(if $(BR2_PACKAGE_LIBICONV),libiconv)
-- 
2.19.1