tools: add HOSTCFLAGS from openssl pkg-config

HOSTCFLAGS of some tools components (image-host, rsa-sign and
ecdsa-libcrypto) depend on the directory where openssl is installed.
Add them via pkg-config.
This fixes a potential build failure in tools when openssl in installed
in varied directories.

Signed-off-by: Raymond Mao <raymond.mao@linaro.org>
Reviewed-by: Peter Robinson <pbrobinson@gmail.com>
1 file changed