openssl: auto-detect `SSL_R_TLSV13_ALERT_CERTIFICATE_REQUIRED`

OpenSSL 1.1.1 defines this macro, but no ealier version, or any of the
popular forks (yet). Use the macro itself to detect its presence,
replacing the hard-wired fork-specific conditions.

This way the feature will enable automatically when forks implement it,
while also shorter and possibly requiring less future maintenance.

Follow-up to 94241a9e78397a2aaf89a213e6ada61e7de7ee02 #6721

Reviewed-by: Jay Satiro
Closes #11617

diff --git a/lib/vtls/openssl.c b/lib/vtls/openssl.c
index 924cd1c7e22096b4767d36963b5d2a532e06faa6..88fd0ed63490ad41f2a871e62a7272ac1777083d 100644 (file)
--- a/lib/vtls/openssl.c
+++ b/lib/vtls/openssl.c
@@ -3903,11 +3903,7 @@ static CURLcode ossl_connect_step2(struct Curl_cfilter *cf,
              error_buffer */
           strcpy(error_buffer, "SSL certificate verification failed");
       }
-#if (OPENSSL_VERSION_NUMBER >= 0x10101000L &&   \
-     !defined(LIBRESSL_VERSION_NUMBER) &&       \
-     !defined(OPENSSL_IS_BORINGSSL) &&          \
-     !defined(OPENSSL_IS_AWSLC))
-
+#if defined(SSL_R_TLSV13_ALERT_CERTIFICATE_REQUIRED)
       /* SSL_R_TLSV13_ALERT_CERTIFICATE_REQUIRED is only available on
          OpenSSL version above v1.1.1, not LibreSSL, BoringSSL, or AWS-LC */
       else if((lib == ERR_LIB_SSL) &&