added a missing CMakeLists.txt file.

src/external/nexus/CMakeLists.txt

@@ -0,0 +1,32 @@
+# - PNeXus library ------------------------------------------------------------
+
+include_directories(${NEXUS_INCLUDE_DIR}) # to get the nexus headers
+
+#--- create pkg-config info ---------------------------------------------------
+set(prefix "${CMAKE_INSTALL_PREFIX}")   
+set(exec_prefix "\$\{prefix\}")
+set(libdir "\$\{exec_prefix\}/lib")
+set(includedir "\$\{prefix\}/include")   
+set(PNEXUS_VERSION "0.9.0")
+set(PNEXUS_LIBRARY_NAME "PNeXus")
+configure_file("PNeXus.pc.in" "PNeXus.pc" @ONLY)
+
+#--- lib creation -------------------------------------------------------------
+add_library(PNeXus SHARED
+  PNeXus.cpp
+)
+
+#--- add library dependencies -------------------------------------------------
+target_link_libraries(PNeXus ${NEXUS_LIBRARY})
+
+#--- install PNeXus solib -----------------------------------------------------
+install(TARGETS PNeXus DESTINATION lib)
+
+#--- install PNeXus header ----------------------------------------------------
+install(FILES PNeXus.h DESTINATION include)
+
+#--- install pkg-config info --------------------------------------------------
+install(
+  FILES ${CMAKE_CURRENT_BINARY_DIR}/PNeXus.pc
+  DESTINATION lib/pkgconfig
+)