move GNU makefiles to name 'GNUmakefile'

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
include/msvc: adding for MSVC build compatibility

These are needed on Visual Studio 2012 and older, but not on Visual Studio
2013.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
hz.c: remove unused unistd.h include

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
hz.c: add definition for snprintf on Visual C++

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
hz.c: change uint64_t to int64_t

Visual C++ 6.0 doesn't like converting uint64 to double for some reason.
Converting to signed int64 looks OK for now.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
libtime.c: add definitions of fmax/fmin for Visual C++

Visual C++ isn't C99-compatible, so we have to define these on our own.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
libtime.c: eliminate 'ULL' integer suffixes

Visual C++ 6.0 doesn't like it, so whatever.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
libtime.h: implement libtime_cpu() on Visual C++ 6.0

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
libtime.c: use "constant" for cycles size

Visual C++ complains that NR_TIME_ITERS isn't a constant expression (despite
the fact that NR_TIME_ITERS is a 'const int'). It's simple enough to fix with
some sizeof() expressions.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>