debian/changelog

+libosmium (2.15.1-2) UNRELEASED; urgency=medium
+
+  * Define ACCEPT_USE_OF_DEPRECATED_PROJ_API_H for PROJ 6.0.0 compatibility.
+  * Update gbp.conf to use --source-only-changes by default.
+
+ -- Bas Couwenberg <sebastic@debian.org>  Sun, 14 Apr 2019 16:01:20 +0200
+
 libosmium (2.15.1-1) unstable; urgency=medium
 
   * New upstream release.

debian/gbp.conf

@@ -14,3 +14,6 @@ upstream-tag = upstream/%(version)s
 
 # Always use pristine-tar.
 pristine-tar = True
+
+[buildpackage]
+pbuilder-options = --source-only-changes

debian/rules

@@ -5,6 +5,9 @@
 # Verbose make output
 export VERBOSE=1
 
+# Workaround for proj_api.h deprecation in PROJ 6.0.0
+export DEB_CXXFLAGS_MAINT_APPEND=-DACCEPT_USE_OF_DEPRECATED_PROJ_API_H
+
 DEB_BUILD_ARCH ?= $(shell dpkg-architecture -qDEB_BUILD_ARCH)
 
 %: