build: Use -fstack-protector-strong

Size difference:

	 wolfssl-util:     file format elf64-x86-64

	 Sections:
	 Idx Name          Size      VMA               LMA               File off  Algn
	   0 .interp       0000001c  0000000000000238  0000000000000238  00000238  2**0
	                   CONTENTS, ALLOC, LOAD, READONLY, DATA
	   1 .note.ABI-tag 00000020  0000000000000254  0000000000000254  00000254  2**2
	                   CONTENTS, ALLOC, LOAD, READONLY, DATA
	-  2 .hash         00000154  0000000000000278  0000000000000278  00000278  2**3
	+  2 .hash         00000158  0000000000000278  0000000000000278  00000278  2**3
	                   CONTENTS, ALLOC, LOAD, READONLY, DATA
	-  3 .dynsym       00000450  00000000000003d0  00000000000003d0  000003d0  2**3
	+  3 .dynsym       00000468  00000000000003d0  00000000000003d0  000003d0  2**3
	                   CONTENTS, ALLOC, LOAD, READONLY, DATA
	-  4 .dynstr       000002ab  0000000000000820  0000000000000820  00000820  2**0
	+  4 .dynstr       000002c6  0000000000000838  0000000000000838  00000838  2**0
	                   CONTENTS, ALLOC, LOAD, READONLY, DATA
	-  5 .gnu.version  0000005c  0000000000000acc  0000000000000acc  00000acc  2**1
	+  5 .gnu.version  0000005e  0000000000000afe  0000000000000afe  00000afe  2**1
	                   CONTENTS, ALLOC, LOAD, READONLY, DATA
	-  6 .gnu.version_r 00000020  0000000000000b28  0000000000000b28  00000b28  2**3
	+  6 .gnu.version_r 00000030  0000000000000b60  0000000000000b60  00000b60  2**3
	                   CONTENTS, ALLOC, LOAD, READONLY, DATA
	-  7 .rela.dyn     00000408  0000000000000b48  0000000000000b48  00000b48  2**3
	+  7 .rela.dyn     00000420  0000000000000b90  0000000000000b90  00000b90  2**3
	                   CONTENTS, ALLOC, LOAD, READONLY, DATA
	-  8 .init         00000017  0000000000000f50  0000000000000f50  00000f50  2**2
	+  8 .init         00000017  0000000000000fb0  0000000000000fb0  00000fb0  2**2
	                   CONTENTS, ALLOC, LOAD, READONLY, CODE
	-  9 .plt          00000010  0000000000000f70  0000000000000f70  00000f70  2**4
	+  9 .plt          00000010  0000000000000fd0  0000000000000fd0  00000fd0  2**4
	                   CONTENTS, ALLOC, LOAD, READONLY, CODE
	- 10 .plt.got      00000110  0000000000000f80  0000000000000f80  00000f80  2**3
	+ 10 .plt.got      00000118  0000000000000fe0  0000000000000fe0  00000fe0  2**3
	                   CONTENTS, ALLOC, LOAD, READONLY, CODE
	- 11 .text         00000742  0000000000001090  0000000000001090  00001090  2**4
	+ 11 .text         000007a2  0000000000001100  0000000000001100  00001100  2**4
	                   CONTENTS, ALLOC, LOAD, READONLY, CODE
	- 12 .fini         00000009  00000000000017d4  00000000000017d4  000017d4  2**2
	+ 12 .fini         00000009  00000000000018a4  00000000000018a4  000018a4  2**2
	                   CONTENTS, ALLOC, LOAD, READONLY, CODE
	- 13 .rodata       0000017e  00000000000017e0  00000000000017e0  000017e0  2**3
	+ 13 .rodata       0000017e  00000000000018b0  00000000000018b0  000018b0  2**3
	                   CONTENTS, ALLOC, LOAD, READONLY, DATA
	- 14 .eh_frame_hdr 00000034  0000000000001960  0000000000001960  00001960  2**2
	+ 14 .eh_frame_hdr 00000034  0000000000001a30  0000000000001a30  00001a30  2**2
	                   CONTENTS, ALLOC, LOAD, READONLY, DATA
	- 15 .eh_frame     000000ec  0000000000001998  0000000000001998  00001998  2**3
	+ 15 .eh_frame     000000ec  0000000000001a68  0000000000001a68  00001a68  2**3
	                   CONTENTS, ALLOC, LOAD, READONLY, DATA
	- 16 .init_array   00000008  0000000000201cc8  0000000000201cc8  00001cc8  2**3
	+ 16 .init_array   00000008  0000000000201cc0  0000000000201cc0  00001cc0  2**3
	                   CONTENTS, ALLOC, LOAD, DATA
	- 17 .fini_array   00000008  0000000000201cd0  0000000000201cd0  00001cd0  2**3
	+ 17 .fini_array   00000008  0000000000201cc8  0000000000201cc8  00001cc8  2**3
	                   CONTENTS, ALLOC, LOAD, DATA
	- 18 .jcr          00000008  0000000000201cd8  0000000000201cd8  00001cd8  2**3
	+ 18 .jcr          00000008  0000000000201cd0  0000000000201cd0  00001cd0  2**3
	                   CONTENTS, ALLOC, LOAD, DATA
	- 19 .dynamic      000001d0  0000000000201ce0  0000000000201ce0  00001ce0  2**3
	+ 19 .dynamic      000001d0  0000000000201cd8  0000000000201cd8  00001cd8  2**3
	                   CONTENTS, ALLOC, LOAD, DATA
	- 20 .got          00000150  0000000000201eb0  0000000000201eb0  00001eb0  2**3
	+ 20 .got          00000158  0000000000201ea8  0000000000201ea8  00001ea8  2**3
	                   CONTENTS, ALLOC, LOAD, DATA
	  21 .data         00000008  0000000000202000  0000000000202000  00002000  2**3
	                   CONTENTS, ALLOC, LOAD, DATA
	  22 .bss          00000010  0000000000202020  0000000000202020  00002008  2**5
	                   ALLOC
	  23 .comment      00000026  0000000000000000  0000000000000000  00002008  2**0
	                   CONTENTS, READONLY

1 files changed, 1 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 9076a6e..2b9aee6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -90,6 +90,7 @@ AX_APPEND_FLAG([-DECC_TIMING_RESISTANT])
 
 for flag in -Os -s -fno-unwind-tables -fno-asynchronous-unwind-tables \
 		-ffunction-sections -fdata-sections -Wl,--gc-sections \
+		-fstack-protector-strong \
 		-Wl,-z,now -Wl,--hash-style=sysv -Wl,--build-id=none; do
 	AX_CHECK_COMPILE_FLAG([${flag}], [AX_APPEND_FLAG([${flag}])])
 done