graphics/mesa: Fix pr247138, detect sys/sysctl.h and fix sed

[zeising]

Summary

This is a round up of misc fixes to mesea ports:
Fix pr247138 by properly defining _GNU_SOURCE when building on FreeBSD. This was lost when moving from autotools to meson
Properly detect sys/sysctl.h on FreeBSD, it requres sys/types.h.
Fix a broken sed command to properly set ${PREFIX}/etc and ${PREFIX}/share as appropriate.

Test Plan

Build and see that -D_GNU_SOURCE and -DHAVE_SYS_SYSCTL_H is set on the command line.
Verify that the sed command actually worked by checking the resulting src/util/xmlconfig.c .

[manu]

Thanks for fixing thoses issues.

head/graphics/libosmesa/Makefile

 dev/iicbus/twsi/mv_twsi.c       optional        twsi
 dev/mge/if_mge.c                optional        mge
 dev/nand/nfc_mv.c               optional        nand
 dev/mvs/mvs_soc.c               optional        mvs
 dev/uart/uart_dev_ns8250.c      optional        uart
 dev/uart/uart_dev_snps.c        optional        uart
 dev/usb/controller/ehci_mv.c    optional        ehci
 dev/usb/controller/xhci_mv.c    optional        xhci
+dev/ahci/ahci_mv_fdt.c          optional        ahci
 
 kern/kern_clocksource.c         standard

head/graphics/libxatracker/Makefile

 dev/iicbus/twsi/mv_twsi.c       optional        twsi
 dev/mge/if_mge.c                optional        mge
 dev/nand/nfc_mv.c               optional        nand
 dev/mvs/mvs_soc.c               optional        mvs
 dev/uart/uart_dev_ns8250.c      optional        uart
 dev/uart/uart_dev_snps.c        optional        uart
 dev/usb/controller/ehci_mv.c    optional        ehci
 dev/usb/controller/xhci_mv.c    optional        xhci
+dev/ahci/ahci_mv_fdt.c          optional        ahci
 
 kern/kern_clocksource.c         standard

head/graphics/mesa-dri/Makefile

 dev/iicbus/twsi/mv_twsi.c       optional        twsi
 dev/mge/if_mge.c                optional        mge
 dev/nand/nfc_mv.c               optional        nand
 dev/mvs/mvs_soc.c               optional        mvs
 dev/uart/uart_dev_ns8250.c      optional        uart
 dev/uart/uart_dev_snps.c        optional        uart
 dev/usb/controller/ehci_mv.c    optional        ehci
 dev/usb/controller/xhci_mv.c    optional        xhci
+dev/ahci/ahci_mv_fdt.c          optional        ahci
 
 kern/kern_clocksource.c         standard

head/graphics/mesa-dri/Makefile.targets

 dev/iicbus/twsi/mv_twsi.c       optional        twsi
 dev/mge/if_mge.c                optional        mge
 dev/nand/nfc_mv.c               optional        nand
 dev/mvs/mvs_soc.c               optional        mvs
 dev/uart/uart_dev_ns8250.c      optional        uart
 dev/uart/uart_dev_snps.c        optional        uart
 dev/usb/controller/ehci_mv.c    optional        ehci
 dev/usb/controller/xhci_mv.c    optional        xhci
+dev/ahci/ahci_mv_fdt.c          optional        ahci
 
 kern/kern_clocksource.c         standard