unix: rename linux/core.c to linux/linux-core.c

Newer versions of gyp do not support files with the same basenames (example:
core.c and linux/core.c).

The nominal reason is consistency across build systems. Apparently, msbuild
doesn't support it either.

Somewhere, someplace, baby Jesus cries sad little tears...

Fixes #464.

config-unix.mk

@@ -67,7 +67,9 @@ EIO_CONFIG=config_linux.h
 CSTDFLAG += -D_GNU_SOURCE
 CPPFLAGS += -Isrc/ares/config_linux
 LINKFLAGS+=-ldl -lrt
-OBJS += src/unix/linux/core.o src/unix/linux/inotify.o src/unix/linux/syscalls.o
+OBJS += src/unix/linux/linux-core.o \
+        src/unix/linux/inotify.o    \
+        src/unix/linux/syscalls.o
 endif
 
 ifeq (FreeBSD,$(uname_S))

uv.gyp

@@ -233,7 +233,7 @@
         [ 'OS=="linux"', {
           'include_dirs': [ 'src/ares/config_linux' ],
           'sources': [
-            'src/unix/linux/core.c',
+            'src/unix/linux/linux-core.c',
             'src/unix/linux/inotify.c',
             'src/unix/linux/syscalls.c',
             'src/unix/linux/syscalls.h',