Changes committed to openembedded-core master within the last 24hrs have broken the mbed Linux build which uses meta-linaro:

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02:48:15 ERROR: Logfile of failure stored in: /work/machine-imx7s-warp-mbl/mbl-manifest/build-mbl/tmp-mbl-glibc/work/cortexa7hf-neon-oe-linux-gnueabi/optee-client/2.6.0+gitAUTOINC+73b4e490a8-r0/temp/log.do_compile.12265
02:48:15 Log data follows:
02:48:15 | DEBUG: Executing shell function do_compile
02:48:15 | NOTE: make -j 24
02:48:15 | Building libteec.so
02:48:15 |   CC      src/tee_client_api.c
02:48:15 |   CC      src/teec_trace.c
02:48:15 | src/teec_trace.c: In function '_dprintf':
02:48:15 | src/teec_trace.c:110:24: error: '%s' directive output may be truncated writing up to 255 bytes into a region of size 246 [-Werror=format-truncation=]
02:48:15 |      "%s [%d] %s:%s:%d: %s",
02:48:15 |                         ^~
02:48:15 | src/teec_trace.c:112:11:
02:48:15 |      line, raw);
02:48:15 |            ~~~
02:48:15 | src/teec_trace.c:109:3: note: 'snprintf' output 11 or more bytes (assuming 266) into a destination of size 256
02:48:15 |    snprintf(prefixed, MAX_PRINT_SIZE,
02:48:15 |    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
02:48:15 |      "%s [%d] %s:%s:%d: %s",
02:48:15 |      ~~~~~~~~~~~~~~~~~~~~~~~
02:48:15 |      trace_level_strings[level], thread_id, prefix, func,
02:48:15 |      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
02:48:15 |      line, raw);
02:48:15 |      ~~~~~~~~~~
02:48:15 | cc1: all warnings being treated as errors
02:48:15 | Makefile:52: recipe for target '/work/machine-imx7s-warp-mbl/mbl-manifest/build-mbl/tmp-mbl-glibc/work/cortexa7hf-neon-oe-linux-gnueabi/optee-client/2.6.0+gitAUTOINC+73b4e490a8-r0/git/libteec/../out/libteec/teec_trace.o' failed
02:48:15 | make[1]: *** [/work/machine-imx7s-warp-mbl/mbl-manifest/build-mbl/tmp-mbl-glibc/work/cortexa7hf-neon-oe-linux-gnueabi/optee-client/2.6.0+gitAUTOINC+73b4e490a8-r0/git/libteec/../out/libteec/teec_trace.o] Error 1
02:48:15 | make[1]: *** Waiting for unfinished jobs....
02:48:15 | Makefile:31: recipe for target 'build-libteec' failed
02:48:15 | make: *** [build-libteec] Error 2
02:48:15 | ERROR: oe_runmake failed
02:48:15 | WARNING: exit code 1 from a shell command.
02:48:15 | ERROR: Function failed: do_compile (log file is located at /work/machine-imx7s-warp-mbl/mbl-manifest/build-mbl/tmp-mbl-glibc/work/cortexa7hf-neon-oe-linux-gnueabi/optee-client/2.6.0+gitAUTOINC+73b4e490a8-r0/temp/log.do_compile.12265)
02:48:15 NOTE: recipe optee-client-2.6.0+gitAUTOINC+73b4e490a8-r0: task do_compile: Failed
02:48:15 NOTE: recipe alsa-state-0.2.0-r5: task do_install: Succeeded
02:48:15 ERROR: Task (/work/machine-imx7s-warp-mbl/mbl-manifest/build-mbl/conf/../../layers/meta-linaro/meta-optee/recipes-security/optee/optee-client.bb:do_compile) failed with exit code '1'
02:48:15 NOTE: recipe modutils-initscripts-1.0-r7: task do_install: Started
===================================================================

between
openembedded-core master commit bad: 8ab5b439ea82ac775494a0ce7a6f3615b61c94be
openembedded-core master commit good:23f15c63777020f5d43b070a1eb2bcf246c19ff8

Here is the diff between mbl-manifest pinned-manifest.xml's between <bad build nad >good build

simhug01@mbed-linux-test:/mnt/data/default_20180613_122141/mbl-manifest$ cat ../manifest_xml_changes.txt 
20,21c20,21
<   <project name="openembedded/meta-openembedded" path="layers/meta-openembedded" remote="github" revision="d9e257abbe16b9d30171493fa8f1d7e2d24cefe5" upstream="master"/>
<   <project name="openembedded/openembedded-core" path="layers/openembedded-core" remote="github" revision="8ab5b439ea82ac775494a0ce7a6f3615b61c94be" upstream="master"/>
---
>   <project name="openembedded/meta-openembedded" path="layers/meta-openembedded" remote="github" revision="bb57bac845f3cd1634862fa9868bc8e294ba74a9" upstream="master"/>
>   <project name="openembedded/openembedded-core" path="layers/openembedded-core" remote="github" revision="23f15c63777020f5d43b070a1eb2bcf246c19ff8" upstream="master"/>

Other triage information: 

triage:
◾This build succeeded: http://xxxxx/job/mbl-master/559/
◾This build failed: http://xxxxx//job/mbl-master/560/
◾The only projects that added changes between these to versions are openembedded-core and meta-openembedded (not meta-linaro containing meta-optee which holds the breaking optee-client.bb recipe).
◾Pinning oe-core in default.xml manifest to build 559 pin builds successfully (leaving meta-oe at head of master).
◾Pinning meta-oe in default manifest to build 559 pin doesn't build successfully (leaving oe-core at head of master).
◾Numerous oe-core changes have been added wrt gcc compiler recipes. Likely that a compiler option has been added to treat certain warnings as errors causing the latest break.
◾Should notify linaro project of the break and see if they fix it, or whether oe-core changes accommodate (less likely).

Approach Linaro staff member Ryan Harkin as a Linaro interface to bug logger.

Thanks
Simon