diff --git a/configure.ac b/configure.ac
index 6d112b8c2f2371c14560d94f0682872dee0eb70b..c99f9eee95a15dc06a040b0f8209ed9e6e8983a0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -422,7 +422,7 @@ AH_BOTTOM([
 #endif
 ])
 
-
+AM_CONDITIONAL(WIN32, test "x$bwin32" = "xtrue")
 AM_CONDITIONAL(BUILD_NT_SERVICES, test "x$bwin32" = "xtrue")
 AM_CONDITIONAL(BUILD_LIBTORRUNNER, test "x$bwin32" != "xtrue")
 
diff --git a/src/lib/log/include.am b/src/lib/log/include.am
index 22b141d3169a8be64bd9d425946c253d86b5b618..f0491b3863ab8561567135c50c1751355d798ca2 100644
--- a/src/lib/log/include.am
+++ b/src/lib/log/include.am
@@ -9,8 +9,11 @@ src_lib_libtor_log_a_SOURCES =			\
 	src/lib/log/escape.c			\
 	src/lib/log/ratelim.c			\
 	src/lib/log/torlog.c			\
-	src/lib/log/util_bug.c			\
-	src/lib/log/win32err.c
+	src/lib/log/util_bug.c
+
+if WIN32
+src_lib_libtor_log_a_SOURCES += src/lib/log/win32err.c
+endif
 
 src_lib_libtor_log_testing_a_SOURCES = \
 	$(src_lib_libtor_log_a_SOURCES)