[meta-java][PATCH] openjdk-8: fix compiler detection

[Patrick Ohly <patrick.ohly@intel.com>]

When GCC is at version 4 or 5, parsing the recipe fails with:

ERROR: ExpansionError during parsing
.../ostro-os/meta-java/recipes-core/openjdk/openjdk-8_72b05.bb
...
bb.data_smart.ExpansionError: Failure expanding variable CFLAGS,
expression was  -O2 -pipe -g -feliminate-unused-debug-types
-fdebug-prefix-map=.../ostro-os/build/tmp-glibc/work/corei7-64-ostro-
linux/openjdk-8/72b05-r0=/usr/src/debug/openjdk-8/72b05-r0
-fdebug-prefix-map=.../ostro-os/build/tmp-glibc/sysroots/x86_64-linux=
-fdebug-prefix-map=.../ostro-os/build/tmp-glibc/sysroots/intel-corei7-64=
 -fstack-protector-strong -D_FORTIFY_SOURCE=2
${ <at> version_specific_cflags(d)} -Wno-error=deprecated-declarations which
triggered exception TypeError: can only join an iterable

That's because FLAGS_GCC<version> may be unset, thus leading to
d.getVar() returning None and ''.join(extraflags) failing.

The join() is also redundant: extraflags already is a string. It
happened to work because Python treats a string as sequence of
single-character strings, and thus ''.join() re-created the original
string.

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
---
 recipes-core/openjdk/openjdk-8-common.inc | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/recipes-core/openjdk/openjdk-8-common.inc b/recipes-core/openjdk/openjdk-8-common.inc
index 089f907..7ad802a 100644
--- a/recipes-core/openjdk/openjdk-8-common.inc
+++ b/recipes-core/openjdk/openjdk-8-common.inc
@@ -271,10 +271,8 @@ def version_specific_cflags(d):
         # doesn't work anyway.
         version = d.getVar('GCCVERSION', expand=True)[0]
 
-    if int(version) >= 4:
-        extraflags = d.getVar('FLAGS_GCC%d' % int(version), True)
-
-    return ''.join(extraflags)
+    extraflags = d.getVar('FLAGS_GCC%d' % int(version), True) or ''
+    return extraflags
 
 CFLAGS_append = " ${@version_specific_cflags(d)}"
 CXXFLAGS_append = " ${@version_specific_cflags(d)}"
-- 
2.1.4