Building on my HiKey, which is Aarch64.
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$ gcc --version gcc (Debian/Linaro 4.9.2-10+deb8u1) 4.9.2 Copyright (C) 2014 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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gcc -I. -I/usr/local/include -DNDEBUG -DHAVE_CONFIG_H -g2 -O2 -fPIC -ggdb3 -Wno-pointer-sign -Wall -W -Wmissing-prototypes -Wmissing-declarations -Wstrict-prototypes -Wpointer-arith -Wbad-function-cast -Wnested-externs -fpic -MT rsa-sign-tr.o -MD -MP -MF rsa-sign-tr.o.d -c rsa-sign-tr.c \ && true gcc -I. -I/usr/local/include -DNDEBUG -DHAVE_CONFIG_H -g2 -O2 -fPIC -ggdb3 -Wno-pointer-sign -Wall -W -Wmissing-prototypes -Wmissing-declarations -Wstrict-prototypes -Wpointer-arith -Wbad-function-cast -Wnested-externs -fpic -MT rsa-verify.o -MD -MP -MF rsa-verify.o.d -c rsa-verify.c \ && true rsa-sign-tr.c: In function ‘sec_equal’: rsa-sign-tr.c:243:3: error: ‘for’ loop initial declarations are only allowed in C99 or C11 mode for (size_t i = 0; i < limbs; i++) ^ rsa-sign-tr.c:243:3: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code Makefile:260: recipe for target 'rsa-sign-tr.o' failed make[1]: *** [rsa-sign-tr.o] Error 1 make[1]: *** Waiting for unfinished jobs.... make[1]: Leaving directory '/home/build/nettle-3.4.1' Makefile:49: recipe for target 'all' failed make: *** [all] Error 2