diff --git a/src/variable.c b/src/variable.c
index d9e1a4a6..94e925fb 100644
--- a/src/variable.c
+++ b/src/variable.c
@@ -282,6 +282,8 @@ define_variable_in_set (const char *name, size_t length,
 
   v->export = v_default;
   v->exportable = 1;
+  /* Check the nul-terminated variable name.  */
+  name = v->name;
   if (*name != '_' && (*name < 'A' || *name > 'Z')
       && (*name < 'a' || *name > 'z'))
     v->exportable = 0;
diff --git a/tests/scripts/features/targetvars b/tests/scripts/features/targetvars
index 66c7ce2d..08263bf3 100644
--- a/tests/scripts/features/targetvars
+++ b/tests/scripts/features/targetvars
@@ -281,6 +281,16 @@ all: ; $sname
 unlink("sd/$sname");
 rmdir ('sd');
 
+# SV 59230: Conditional (non-)assignment of target-specific variables should
+# preserve export settings.
+
+$ENV{hello} = 'moon';
+run_make_test(q!
+all:; @echo hello=$$hello
+dummy: hello?=world
+!,
+              '', 'hello=moon');
+
 # TEST #19: Test define/endef variables as target-specific vars
 
 # run_make_test('