expat: fix build on and for kernel older than 3.17

The expat build system now fails when the getrandom() system call is not
supported. This affect both host and target builds. Define XML_POOR_ENTROPY
for target kernels older than 3.17 to fix the build. For the host package
define XML_POOR_ENTROPY unconditionally since we have no easy way to know the
host kernel version. Note that expat will still use getrandom() on the host
when it is available, we don't make security any worse.

Fixes (host):
http://autobuild.buildroot.net/results/928/928dc2b56d931da84055fdfe78929d1f956de53b/
http://autobuild.buildroot.net/results/ee9/ee90d0a456cbce4c7f22e5f61006612bd9ba30d5/
http://autobuild.buildroot.net/results/dac/dac7231242123ae3dcaa6bbdd65b44fe8d8cb20c/

Fixes (target):
http://autobuild.buildroot.net/results/308/308e830219fdfebb5aa6aef51c1dc784254998f6/
http://autobuild.buildroot.net/results/73f/73fa946b0a2205e946ad414079f88e4bdb416f00/
http://autobuild.buildroot.net/results/9d7/9d7bad22ace7fa211b31d752a2255e07cede68be/

[Peter: also use HOST_CPPFLAGS]
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

diff --git a/package/expat/expat.mk b/package/expat/expat.mk
index a10f2c974aa67fa087a4e4c3f6b8f16a0201cd98..a78d326d71107aa32dd7355cd37beec18bf2322c 100644 (file)
--- a/package/expat/expat.mk
+++ b/package/expat/expat.mk
@@ -15,5 +15,14 @@ HOST_EXPAT_DEPENDENCIES = host-pkgconf
 EXPAT_LICENSE = MIT
 EXPAT_LICENSE_FILES = COPYING
 
+# Kernel versions older than 3.17 do not support getrandom()
+ifeq ($(BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_17),)
+EXPAT_CONF_ENV += CPPFLAGS="$(TARGET_CPPFLAGS) -DXML_POOR_ENTROPY"
+endif
+
+# Make build succeed on host kernel older than 3.17. getrandom() will still
+# be used on newer kernels.
+HOST_EXPAT_CONF_ENV += CPPFLAGS="$(HOST_CPPFLAGS) -DXML_POOR_ENTROPY"
+
 $(eval $(autotools-package))
 $(eval $(host-autotools-package))