Minimum changes required to do "VPATH build"

That is to say, build from a directory other than the source directory.

Makefile.am

@@ -1,4 +1,4 @@
 AUTOMAKE_OPTIONS = foreign
 ACLOCAL_AMFLAGS = -I config
 SUBDIRS = src tools
-DIST_SUBDIRS = src tools
+DIST_SUBDIRS = doc src tools

doc/Makefile.am

@@ -1,3 +1,5 @@
+if BUILD_DOC
+
 MAN1 = 
 MAN3 = zyre.3 zyre_event.3 zre_msg.3 zre_log_msg.3
 MAN7 = 
@@ -31,3 +33,5 @@ SUFFIXES=.txt .xml .1 .3 .7
 .xml.7:
 	xmlto man $<
 endif
+
+endif

src/Makefile.am

@@ -15,6 +15,7 @@ libzyre_la_SOURCES = \
     zyre_peer.h \
     zyre_group.h \
     zyre_node.h \
+    zyre_classes.h \
     zyre_log.c \
     zyre_group.c \
     zyre_peer.c \

tools/Makefile.am

@@ -12,17 +12,17 @@ bin_PROGRAMS = zpinger \
                perf_local \
                perf_remote
 
-zpinger_LDADD = $(top_srcdir)/src/libzyre.la
+zpinger_LDADD = $(top_builddir)/src/libzyre.la
 zpinger_SOURCES = zpinger.c
 
-ztester_LDADD = $(top_srcdir)/src/libzyre.la
+ztester_LDADD = $(top_builddir)/src/libzyre.la
 ztester_SOURCES = ztester.c
 
-zlogger_LDADD = $(top_srcdir)/src/libzyre.la
+zlogger_LDADD = $(top_builddir)/src/libzyre.la
 zlogger_SOURCES = zlogger.c
 
-perf_local_LDADD = $(top_srcdir)/src/libzyre.la
+perf_local_LDADD = $(top_builddir)/src/libzyre.la
 perf_local_SOURCES = perf_local.c
 
-perf_remote_LDADD = $(top_srcdir)/src/libzyre.la
+perf_remote_LDADD = $(top_builddir)/src/libzyre.la
 perf_remote_SOURCES = perf_remote.c