With the latest content of u-boot-mmc/master, 41dc35a149b3 "drivers: mmc: Avoid memory leak in case of failure", all Tegra boards (perhaps others too; my system only tests Tegra) fail to build with the following error:
drivers/built-in.o: In function `mmc_select_mode_and_width': /var/lib/jenkins/workspace/u-boot-denx_uboot_mmc-master-build/src/u-boot/drivers/mmc/mmc.c:1847: undefined reference to `error' drivers/built-in.o: In function `bus_width': /var/lib/jenkins/workspace/u-boot-denx_uboot_mmc-master-build/src/u-boot/drivers/mmc/mmc.c:1436: undefined reference to `error' /var/lib/jenkins/workspace/u-boot-denx_uboot_mmc-master-build/src/u-boot/drivers/mmc/mmc.c:1436: undefined reference to `error' /var/lib/jenkins/workspace/u-boot-denx_uboot_mmc-master-build/src/u-boot/drivers/mmc/mmc.c:1436: undefined reference to `error' drivers/built-in.o: In function `mmc_get_capabilities': /var/lib/jenkins/workspace/u-boot-denx_uboot_mmc-master-build/src/u-boot/drivers/mmc/mmc.c:831: undefined reference to `error' arm-none-eabi-ld.bfd: BFD (2.24-2ubuntu2+4) 2.24 assertion fail ../../binutils-2.24/bfd/elf32-arm.c:7696 arm-none-eabi-ld.bfd: error: required section '.rel.plt' not found in the linker script arm-none-eabi-ld.bfd: final link failed: Invalid operation