Brought CGA code in line with mainline as the patch was accepted.

Uncommented auto-setting FDC data rate to 250 kbps on non-AT machines; fixes floppies on IBM PC and XT and clones;
Removed flto flag from the makefiles, should speed up compile times and make the XT and earlier machines work again;
Removed CGA brown and color burst settings in line with mainline PCem.

src/dosbox/vid_cga_comp.h

@@ -0,0 +1,8 @@
+#define Bit8u uint8_t
+#define Bit32u uint32_t
+#define Bitu unsigned int
+#define bool uint8_t
+
+void update_cga16_color(cga_t *cga);
+void cga_comp_init(cga_t *cga);
+Bit8u * Composite_Process(cga_t *cga, Bit8u border, Bit32u blocks/*, bool doublewidth*/, Bit8u *TempLine);