Remove Makefile.embed

This has not been a supported build mode for quite some time, and it
correspondingly hasn't worked to build the library for a long time. Get
rid of it, as the only build mode we support is though CMakek.

Makefile.embed

-PLATFORM=$(shell uname -s)
-
-ifneq (,$(CROSS_COMPILE))
-	PREFIX=$(CROSS_COMPILE)-
-else
-	PREFIX=
-endif
-
-MINGW=0
-ifneq (,$(findstring MINGW32,$(PLATFORM)))
-	MINGW=1
-endif
-ifneq (,$(findstring mingw,$(CROSS_COMPILE)))
-	MINGW=1
-endif
-
-rm=rm -f
-AR=$(PREFIX)ar cq
-RANLIB=$(PREFIX)ranlib
-
-LIBNAME=libgit2.a
-
-ifeq ($(MINGW),1)
-	CC=gcc
-else
-	CC=cc
-endif
-
-CC:=$(PREFIX)$(CC)
-
-INCLUDES= -I. -Isrc -Iinclude -Ideps/http-parser -Ideps/zlib
-
-DEFINES= $(INCLUDES) -DNO_VIZ -DSTDC -DNO_GZIP -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE $(EXTRA_DEFINES)
-CFLAGS= -g $(DEFINES) -Wall -Wextra -Wno-missing-field-initializers -O2 $(EXTRA_CFLAGS)
-
-SRCS = $(wildcard src/*.c) $(wildcard src/transports/*.c) $(wildcard src/xdiff/*.c) $(wildcard deps/http-parser/*.c) $(wildcard deps/zlib/*.c) src/hash/hash_generic.c
-
-ifeq ($(MINGW),1)
-	SRCS += $(wildcard src/win32/*.c) $(wildcard src/compat/*.c) deps/regex/regex.c
-	INCLUDES += -Ideps/regex
-	DEFINES += -DWIN32 -D_WIN32_WINNT=0x0501 -D__USE_MINGW_ANSI_STDIO=1
-else
-	SRCS += $(wildcard src/unix/*.c) 
-	CFLAGS += -fPIC
-endif
-
-OBJS = $(patsubst %.c,%.o,$(SRCS))
-
-%.c.o:
-	$(CC) $(CFLAGS) -c $*.c
-
-all: $(LIBNAME)
-
-$(LIBNAME): $(OBJS)
-	$(rm) $@
-	$(AR) $@ $(OBJS)
-	$(RANLIB) $@
-
-clean:
-	$(rm) $(OBJS) $(LIBNAME)