pppd: Fix build without OpenSSL #649

Job	Run time
Buildroot (qemu_x86_defconfig, glibc)	1m 40s
Buildroot (qemu_x86_defconfig, uclibc)	1m 36s
Buildroot (qemu_x86_defconfig, musl)	1m 35s
Buildroot (qemu_x86_64_defconfig, glibc)	2m 23s
Buildroot (qemu_x86_64_defconfig, uclibc)	1m 49s
Buildroot (qemu_x86_64_defconfig, musl)	1m 49s
Buildroot (raspberrypi4_defconfig, glibc)	1m 55s
Buildroot (raspberrypi4_defconfig, uclibc)	2m 20s
Buildroot (raspberrypi4_defconfig, musl)	1m 41s
Buildroot (raspberrypi4_64_defconfig, glibc)	2m 32s
Buildroot (raspberrypi4_64_defconfig, uclibc)	2m 18s
Buildroot (raspberrypi4_64_defconfig, musl)	2m 17s
Buildroot (qemu_ppc64le_pseries_defconfig, glibc)	1m 43s
Buildroot (qemu_ppc64le_pseries_defconfig, uclibc)	2m 0s
Buildroot (qemu_ppc64le_pseries_defconfig, musl)	1m 41s
Buildroot (qemu_mips32r2_malta_defconfig, glibc)	1m 42s
Buildroot (qemu_mips32r2_malta_defconfig, uclibc)	2m 17s
Buildroot (qemu_mips32r2_malta_defconfig, musl)	2m 16s
Buildroot (qemu_mips64_malta_defconfig, glibc)	1m 51s
Buildroot (qemu_mips64_malta_defconfig, uclibc)	1m 34s
Buildroot (qemu_mips64_malta_defconfig, musl)	1m 47s
Buildroot (qemu_riscv32_virt_defconfig, glibc)	1m 44s
Buildroot (qemu_riscv32_virt_defconfig, uclibc)	2m 29s
Buildroot (qemu_riscv32_virt_defconfig, musl)	1m 42s
Buildroot (qemu_riscv64_virt_defconfig, glibc)	2m 24s
Buildroot (qemu_riscv64_virt_defconfig, uclibc)	1m 36s
Buildroot (qemu_riscv64_virt_defconfig, musl)	1m 37s
	52m 18s

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