configure.ac: Add libyaml dependency

I'm about to introduce a feature that is configured via YAML
documents. Add a configure.ac dependency for the library to be used
for handling those configuration documents.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Author: chucklever

.github/workflows/makefile.yml

@@ -22,7 +22,7 @@ jobs:
     - name: Install dependencies
       run: |
         sudo apt-get update
-        sudo apt-get -y install gnutls-dev libkeyutils-dev libnl-3-dev libnl-genl-3-dev libglib2.0-dev
+        sudo apt-get -y install gnutls-dev libkeyutils-dev libnl-3-dev libnl-genl-3-dev libglib2.0-dev libyaml-dev
 
     - name: Configure
       run: |

configure.ac

@@ -62,6 +62,9 @@ AC_SUBST([LIBNL3_LIBS])
 PKG_CHECK_MODULES([LIBNL_GENL3], libnl-genl-3.0 >= 3.1)
 AC_SUBST([LIBNL_GENL3_CFLAGS])
 AC_SUBST([LIBNL_GENL3_LIBS])
+PKG_CHECK_MODULES(LIBYAML, [yaml-0.1])
+AC_SUBST([LIBYAML_CFLAGS])
+AC_SUBST([LIBYAML_LIBS])
 
 AC_CHECK_HEADER([linux/quic.h],
               [AC_CHECK_LIB([gnutls], [gnutls_handshake_set_secret_function],

src/tlshd/Makefile.am

@@ -22,11 +22,11 @@ EXTRA_DIST		= $(man8_MANS)
 sbin_PROGRAMS		= tlshd
 tlshd_CFLAGS		= -Werror -Wall -Wextra $(LIBGNUTLS_CFLAGS) \
 			  $(LIBKEYUTILS_CFLAGS) $(GLIB_CFLAGS) $(LIBNL3_CFLAGS) \
-			  $(LIBNL_GENL3_CFLAGS)
+			  $(LIBNL_GENL3_CFLAGS) $(LIBYAML_CFLAGS)
 tlshd_SOURCES		= client.c config.c handshake.c keyring.c ktls.c log.c \
 			  main.c netlink.c netlink.h server.c tlshd.h quic.c
 tlshd_LDADD		= $(LIBGNUTLS_LIBS) $(LIBKEYUTILS_LIBS) $(GLIB_LIBS) \
-			  $(LIBNL3_LIBS) $(LIBNL_GENL3_LIBS)
+			  $(LIBNL3_LIBS) $(LIBNL_GENL3_LIBS) $(LIBYAML_LIBS)
 
 SUBDIRS			= etc
 MAINTAINERCLEANFILES	= Makefile.in cscope.out