Ruby

Revert "Fix redefinition of clock_gettime and clock_getres"

This reverts commit 585598623da949c92d0f2ea94029a863142ec908.

This broke Windows CIs

linking miniruby.exe
   Creating library miniruby.lib and object miniruby.exp
process.obj : error LNK2019: unresolved external symbol clock_gettime referenced in function rb_clock_gettime
random.obj : error LNK2001: unresolved external symbol clock_gettime
thread.obj : error LNK2001: unresolved external symbol clock_gettime
time.obj : error LNK2001: unresolved external symbol clock_gettime
process.obj : error LNK2019: unresolved external symbol clock_getres referenced in function rb_clock_getres
miniruby.exe : fatal error LNK1120: 2 unresolved externals
NMAKE : fatal error U1077: '"C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Tools\MSVC\14.29.30133\bin\HostX64\x64\cl.EXE"' : return code '0x2'