BUG #15132: Build fails in src/backend/utils/adt/encode.c

The following bug has been logged on the website:

Bug reference:      15132
Logged by:          Stefan Krüger
Email address:      stadtkind2@gmx.de
PostgreSQL version: 10.3
Operating system:   Solaris 11.4 Beta
Description:

Hi,

Solaris 11.4 has b64_encode/b64_decode in libc. So building PostgreSQL 10.3
fails because they are defined in src/backend/utils/adt/encode.c as well:

gmake[4]: Entering directory '/tmp/postgresql-10.3/src/backend/utils/adt'
/opt/developerstudio12.6/bin/cc -Xa -m64 -g -Qoption cg -xregs=no%appl
-W2,-xwrap_int -xc99=all -KPIC -DPIC -xmemalign=16s
-I../../../../src/include  -D_LARGEFILE64_SOURCE -D_XOPEN_SOURCE=600
-D__EXTENSIONS__=1 -D_XPG6   -c -o encode.o encode.c
"encode.c", line 218: identifier redeclared: b64_encode
        current : static function(pointer to const char, unsigned int,
pointer to char) returning unsigned int
        previous: function(restrict pointer to char, unsigned long, restrict
pointer to const void, unsigned long, pointer to const char, unsigned long)
returning long : "/usr/include/string.h", line 218
"encode.c", line 265: identifier redeclared: b64_decode
        current : static function(pointer to const char, unsigned int,
pointer to char) returning unsigned int
        previous: function(pointer to void, unsigned long, pointer to const
char, pointer to const char, unsigned long) returning long :
"/usr/include/string.h", line 221
cc: acomp failed for encode.c