4 files changed, 18 insertions, 3 deletions
diff --git a/doc/developer/.gitignore b/doc/developer/.gitignore
index 0505537159..2e7d8573f1 100644
--- a/doc/developer/.gitignore
+++ b/doc/developer/.gitignore
@@ -1,3 +1,3 @@
 /_templates
 /_build
-!/Makefile
+!/Makefile.in
diff --git a/doc/developer/Makefile b/doc/developer/Makefile
deleted file mode 100644
index 9807a750bf..0000000000
--- a/doc/developer/Makefile
+++ /dev/null
@@ -1 +0,0 @@
-include ../frr-sphinx.mk
diff --git a/doc/developer/Makefile.in b/doc/developer/Makefile.in
new file mode 100644
index 0000000000..76758f9242
--- /dev/null
+++ b/doc/developer/Makefile.in
@@ -0,0 +1,8 @@
+# This is necessary to support VPATH builds.
+srcdir = @srcdir@
+VPATH = @srcdir@
+
+# This variable is used as the documentation source location in frr-sphinx.mk
+SOURCESDIR = @srcdir@
+
+include @srcdir@/../frr-sphinx.mk
diff --git a/doc/developer/conf.py b/doc/developer/conf.py
index a3968b60ff..61253c4b2f 100644
--- a/doc/developer/conf.py
+++ b/doc/developer/conf.py
@@ -342,6 +342,14 @@ texinfo_documents = [
 # If true, do not generate a @detailmenu in the "Top" node's menu.
 #texinfo_no_detailmenu = False
 
+# contents of ../extra/frrlexer.py.
+# This is read here to support VPATH build. Since this section is execfile()'d
+# with the file location, we can safely use a relative path here to save the
+# contents of the lexer file for later use even if our relative path changes
+# due to VPATH.
+with open('../extra/frrlexer.py', 'rb') as lex:
+    frrlexerpy = lex.read()
+
 # custom extensions here
 def setup(app):
     # object type for FRR CLI commands, can be extended to document parent CLI
@@ -357,5 +365,5 @@ def setup(app):
     #
     # frrlexer = pygments.lexers.load_lexer_from_file('../extra/frrlexer.py', lexername="FRRLexer")
     custom_namespace = {}
-    exec(open('../extra/frrlexer.py', 'rb').read(), custom_namespace)
+    exec(frrlexerpy, custom_namespace)
     lexers['frr'] = custom_namespace['FRRLexer']()