Add line number+diagnostic function

Author: ralismark

tectonic/xetex-output.c

@@ -53,6 +53,20 @@ diagnostic_error_here(const char *format, ...)
     return error;
 }
 
+// This replaces the "print file+line number" block at the start of errors
+diagnostic_t
+error_here_with_diagnostic(const char* message)
+{
+    diagnostic_t error = diagnostic_error_here("%s", message);
+    if (file_line_error_style_p)
+        print_file_line();
+    else
+        print_nl_cstr("! ");
+    print_cstr(message);
+
+    return error;
+}
+
 static void
 warn_char(int c)
 {

tectonic/xetex-xetexd.h

@@ -1025,6 +1025,7 @@ void flush_math(void);
 
 void capture_to_diagnostic(diagnostic_t warning);
 PRINTF_FUNC(1,2) diagnostic_t diagnostic_error_here(const char *format, ...);
+diagnostic_t error_here_with_diagnostic(const char* message);
 void print_ln(void);
 void print_raw_char(UTF16_code s, bool incr_offset);
 void print_char(int32_t s);