diff --git a/meson.build b/meson.build
index b443b479..aecfff02 100644
--- a/meson.build
+++ b/meson.build
@@ -57,7 +57,7 @@ if otr_dep.found()
 endif
 pgp_dep = dependency('gpgme', required : get_option('pgp'))
 if pgp_dep.found()
-  conf.set_quoted('BUILD_PGP', '1')
+  conf.set_quoted('HAVE_LIBGPGME', '1')
 endif
 # TODO: HAVE_LIBSIGNAL_LT_2_3_2
 omemo_libsignal_dep = dependency('libsignal-protocol-c', version: '>= 2.3.2', required : get_option('pgp'))
@@ -96,7 +96,7 @@ subdir('src')
 # TODO: output build info
 
 profanity = executable('profanity',
-            core_sources_c,
+            sources,
             dependencies : [ glib_dep,
                              gio_dep,
                              curl_dep,
diff --git a/src/meson.build b/src/meson.build
index c2ff132a..c03ebe58 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -1,3 +1,4 @@
+# main sources
 core_sources_c = [ 'src/main.c',
                    'src/profanity.c',
                    'src/log.c',
@@ -73,4 +74,20 @@ core_sources_c = [ 'src/main.c',
                    config_h
 ]
 
+sources = core_sources_c
 incdir = include_directories('.', 'command', 'config', 'ui', 'plugins', 'xmpp')
+
+# optional sources
+
+if pgp_dep.found()
+  sources += 'src/pgp/gpg.c'
+endif
+
+if otr_dep.found()
+  otr_sources = [ 'src/otr/otrlibv4.c',
+                 'src/otr/otr.c',
+                 ]
+  incdir += include_directories('otr')
+
+  sources += otr_sources
+endif