--- a/doc/CMakeLists.txt
+++ b/doc/CMakeLists.txt
@@ -12,7 +12,7 @@
     if(DBLATEX)
         add_custom_command(OUTPUT ${PROJECT_BINARY_DIR}/manual.pdf
                            DEPENDS ${PROJECT_SOURCE_DIR}/[a-z]*.asc
-                           COMMAND ${A2X} -D ${PROJECT_BINARY_DIR} ${PROJECT_SOURCE_DIR}/manual.asc)
+                           COMMAND ${A2X} -D ${PROJECT_BINARY_DIR} --dblatex-opts="--tmpdir=docbuild" ${PROJECT_SOURCE_DIR}/manual.asc)
         add_custom_command(OUTPUT ${PROJECT_BINARY_DIR}/GTF.pdf
                            DEPENDS ${PROJECT_SOURCE_DIR}/GTF.asc
                                    ${PROJECT_SOURCE_DIR}/OpCodes.asc