Fix build failure on HP-UX

$ ./configure
$ make
...
        gcc -DHAVE_CONFIG_H -I. -I../../../include    -I/usr/local/openssl-1.1.1i/include -g -O2 -I/usr/local/include -MT libzbxcrypto_a-base64.o -MD -MP -MF .deps/libzbxcrypto_a-base64.Tpo -c -o libzbxcrypto_a-base64.o `test -f 'base64.c' || echo './'`base64.c
        mv -f .deps/libzbxcrypto_a-base64.Tpo .deps/libzbxcrypto_a-base64.Po
        gcc -DHAVE_CONFIG_H -I. -I../../../include    -I/usr/local/openssl-1.1.1i/include -g -O2 -I/usr/local/include -MT libzbxcrypto_a-md5.o -MD -MP -MF .deps/libzbxcrypto_a-md5.Tpo -c -o libzbxcrypto_a-md5.o `test -f 'md5.c' || echo './'`md5.c
        mv -f .deps/libzbxcrypto_a-md5.Tpo .deps/libzbxcrypto_a-md5.Po
        gcc -DHAVE_CONFIG_H -I. -I../../../include    -I/usr/local/openssl-1.1.1i/include -g -O2 -I/usr/local/include -MT libzbxcrypto_a-sha256crypt.o -MD -MP -MF .deps/libzbxcrypto_a-sha256crypt.Tpo -c -o libzbxcrypto_a-sha256crypt.o `test -f 'sha256crypt.c' || echo './'`sha256crypt.c
sha256crypt.c:12:30: error: machine/endian.h: No such file or directory