2.1.11 fails to build on RHEL 7.8

[johnphamngc]

Describe the bug
2.1.11 fails to build on RHEL 7.8, due to endianness macros, as part of cFS build, with or without devtoolset-9:

[ 14%] Building C object tools/cFS-GroundSystem/Subsystems/cmdUtil/CMakeFiles/cmdUtil.dir/cmdUtil.c.o
cd /tmp/cFS/build/tools/cFS-GroundSystem/Subsystems/cmdUtil && /opt/rh/devtoolset-9/root/usr/bin/cc -D_XOPEN_SOURCE=600  -g   -std=c99 -pedantic -Wall -Wstrict-prototypes -Wwrite-strings -Wpointer-arith -Wcast-align -Werror -o CMakeFiles/cmdUtil.dir/cmdUtil.c.o   -c /tmp/cFS/tools/cFS-GroundSystem/Subsystems/cmdUtil/cmdUtil.c
/tmp/cFS/tools/cFS-GroundSystem/Subsystems/cmdUtil/cmdUtil.c: In function ‘ProcessField’:
/tmp/cFS/tools/cFS-GroundSystem/Subsystems/cmdUtil/cmdUtil.c:370:13: error: implicit declaration of function ‘htobe16’ [-Werror=implicit-function-declaration]
  370 |     *orig = htobe16((be16toh(*orig) & ~mask) | (templong & mask));
      |             ^~~~~~~
/tmp/cFS/tools/cFS-GroundSystem/Subsystems/cmdUtil/cmdUtil.c:370:22: error: implicit declaration of function ‘be16toh’ [-Werror=implicit-function-declaration]
  370 |     *orig = htobe16((be16toh(*orig) & ~mask) | (templong & mask));
      |                      ^~~~~~~
/tmp/cFS/tools/cFS-GroundSystem/Subsystems/cmdUtil/cmdUtil.c: In function ‘main’:
/tmp/cFS/tools/cFS-GroundSystem/Subsystems/cmdUtil/cmdUtil.c:666:33: error: implicit declaration of function ‘htole16’ [-Werror=implicit-function-declaration]
  666 |                     tempint16 = htole16(tempint16);
      |                                 ^~~~~~~
/tmp/cFS/tools/cFS-GroundSystem/Subsystems/cmdUtil/cmdUtil.c:708:33: error: implicit declaration of function ‘htobe32’ [-Werror=implicit-function-declaration]
  708 |                     tempint32 = htobe32(tempint32);
      |                                 ^~~~~~~
/tmp/cFS/tools/cFS-GroundSystem/Subsystems/cmdUtil/cmdUtil.c:710:33: error: implicit declaration of function ‘htole32’ [-Werror=implicit-function-declaration]
  710 |                     tempint32 = htole32(tempint32);
      |                                 ^~~~~~~
/tmp/cFS/tools/cFS-GroundSystem/Subsystems/cmdUtil/cmdUtil.c:752:33: error: implicit declaration of function ‘htobe64’ [-Werror=implicit-function-declaration]
  752 |                     tempint64 = htobe64(tempint64);
      |                                 ^~~~~~~
/tmp/cFS/tools/cFS-GroundSystem/Subsystems/cmdUtil/cmdUtil.c:754:33: error: implicit declaration of function ‘htole64’ [-Werror=implicit-function-declaration]
  754 |                     tempint64 = htole64(tempint64);
      |                                 ^~~~~~~
cc1: all warnings being treated as errors

To Reproduce
Build CFS GroundSystem on RHEL 7.8 as part of the cFS build. However, using the cmdUtil makefile works fine.

Expected behavior
Build completes correctly as part of cFS makefile build

System observed on:

• OS: RHEL 7.8
• Versions : cFS-GroundSystem 2.1.11

Additional context
This is apparently fixed by changing the macro defined at the top of cmdUtil.c from #define _BSD_SOURCE_ to #define _BSD_SOURCE

Reporter Info
John N Pham, Northrop Grumman

[skliper]

Related to #95. Trade is add the _BSD_SOURCE define, use -std=gnu99 (if this works), or re-implement the functions.

[jphickey]

Note, -std=gnu99 does not work for this platform. It is not a GNU extension, and is not enabled by gnu99.

For this to build on RHEL you currently have to add _BSD_SOURCE to mission_build_custom.cmake, in addition to the _XOPEN_SOURCE which may be already there from the example, e.g.:

add_definitions(
    -D_XOPEN_SOURCE=600
    -D_BSD_SOURCE
)

My preference would still be to implement #95 which wouldn't require this extension on some platforms.