diff --git a/lib/deps.Makefile b/lib/deps.Makefile
index d3564146c..e6bca804d 100644
--- a/lib/deps.Makefile
+++ b/lib/deps.Makefile
@@ -1,12 +1,15 @@
 # Define build flags for used dependencies.
 
-$(top_srcdir)/config.mk:
-	$(top_srcdir)/utils/gen-common-flags >$@
+$(top_srcdir)/config.mk: $(top_srcdir)/utils/gen-common-flags \
+		$(top_srcdir)/utils/gen-bcg729-flags \
+		$(top_srcdir)/utils/gen-codec-chain-flags
+	$(top_srcdir)/utils/gen-common-flags >$@.new
 ifeq (,$(filter pkg.ngcp-rtpengine.nobcg729,${DEB_BUILD_PROFILES}))
-	$(top_srcdir)/utils/gen-bcg729-flags >>$@
+	$(top_srcdir)/utils/gen-bcg729-flags >>$@.new
 endif
 ifneq (,$(filter pkg.ngcp-rtpengine.codec-chain,${DEB_BUILD_PROFILES}))
-	$(top_srcdir)/utils/gen-codec-chain-flags >>$@
+	$(top_srcdir)/utils/gen-codec-chain-flags >>$@.new
 endif
+	mv $@.new $@
 
 include $(top_srcdir)/config.mk
diff --git a/utils/gen-common-flags b/utils/gen-common-flags
index 862525442..f9f0531f6 100755
--- a/utils/gen-common-flags
+++ b/utils/gen-common-flags
@@ -5,6 +5,11 @@ gen-pkgconf-flags()
   local var="$1"
   local pc="$2"
 
+  if ! pkg-config --exists "${pc}"; then
+    echo "Error: Required package '${pc}' not found" >&2
+    exit 1
+  fi
+
   echo "export CFLAGS_${var} LDLIBS_${var}"
   echo "CFLAGS_${var} := $(pkg-config --cflags "${pc}")"
   echo "LDLIBS_${var} := $(pkg-config --libs "${pc}")"