RFR: JDK-8199606 Set -lc as global LIBS on solstudio

[Magnus Ihse Bursie]

We should always use -lc when linking with solstudio. All other 
toolchains do this automatically. This also means that -lc is 
unnecessary for other platforms, where it has been set in some cases 
(due to the old confusion where "solaris" really meant "unix").

I have tested this using COMPARE_BUILD. Unsurprisingly, there are 
differences, but they are expected. On macosx and linux, libunpack has 
disassembly differences (they had previously an explicit -lc). On linux, 
the same also goes for libjli, libawt_xawt, libfontmanager and libsunec.

On solaris there are even more differences. Now all libraries get 
explicitely linked with -lc, which means binary/disassembly differences 
in multiple libraries.  We also get a deps difference for libjsig and 
librmi, which were previously compiled (successfully, for a change! :-)) 
without -lc. Finally, we get a symbol difference for libjava.We're 
missing symbols like: "a s_finite.c" and "t finite", and we have one 
less duplicate of "r two54". I can't say I understand why, but it does 
seem harmless.

Bug: https://bugs.openjdk.java.net/browse/JDK-8199606
WebRev: 
http://cr.openjdk.java.net/~ihse/JDK-8199606-set-lc-as-GLOBAL_LIBS/webrev.01

/Magnus