krb5 commit: Fix typo in musl build fix

https://github.com/krb5/krb5/commit/b009cca2026b615ef5386faa4c0230bc27c4161d
commit b009cca2026b615ef5386faa4c0230bc27c4161d
Author: Greg Hudson <[email protected]>
Date:   Thu Mar 12 00:44:10 2020 -0400

    Fix typo in musl build fix
    
    Commit cbdbc8d00d31344fafe00e0fdf984e04e631f7c4 checked for
    __GLIBC__PREREQ instead of __GLIBC_PREREQ, thus accidentally reverting
    the workaround introduced in commit
    bf5953c549a6d279977df69ffe89b2ba51460eaf.  Fix the typo.
    
    ticket: 8880

 src/util/support/plugins.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/util/support/plugins.c b/src/util/support/plugins.c
index 1644d16..1ff10c3 100644
--- a/src/util/support/plugins.c
+++ b/src/util/support/plugins.c
@@ -62,7 +62,7 @@
  * dlopen() with RTLD_NODELETE, we weren't going to unload the plugin objects
  * anyway.
  */
-#ifdef __GLIBC__PREREQ
+#ifdef __GLIBC_PREREQ
 #if ! __GLIBC_PREREQ(2, 25)
 #define dlclose(x)
 #endif