Byron Stanoszek reports:
-----------------------
I have a small bug report for you concerning libcap-2.51. It fails to compile
out of the box on RedHat Enterprise Linux 7.6 due to the following error:

# make
...
uns_test.c: In function ‘main’:
uns_test.c:118:5: error: ‘for’ loop initial declarations are only allowed in C99 mode
      for (int i=0; i<2; i++) {
      ^
uns_test.c:118:5: note: use option -std=c99 or -std=gnu99 to compile your code
make[2]: *** [uns_test] Error 1
make[2]: Leaving directory `/root/src/rhel7-os-update/libcap-2.51/tests'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/root/src/rhel7-os-update/libcap-2.51/tests'
make: *** [all] Error 2

# gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/4.8.5/lto-wrapper
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-linker-hash-style=gnu --enable-languages=c,c++,objc,obj-c++,java,fortran,ada,go,lto --enable-plugin --enable-initfini-array --disable-libgcj --with-isl=/builddir/build/BUILD/gcc-4.8.5-20150702/obj-x86_64-redhat-linux/isl-install --with-cloog=/builddir/build/BUILD/gcc-4.8.5-20150702/obj-x86_64-redhat-linux/cloog-install --enable-gnu-indirect-function --with-tune=generic --with-arch_32=x86-64 --build=x86_64-redhat-linux
Thread model: posix
gcc version 4.8.5 20150623 (Red Hat 4.8.5-36) (GCC)

# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 7.6 (Maipo)