[Minor] Some tweaks to the cmake scripts

CMakeLists.txt

@@ -402,6 +402,11 @@ ELSE(HAVE_PCRE_JIT_FAST)
 ENDIF(HAVE_PCRE_JIT_FAST)
 ENDIF()
 
+CHECK_C_COMPILER_FLAG(-fPIC SUPPORT_FPIC)
+IF(SUPPORT_FPIC)
+	ADD_COMPILE_OPTIONS("-fPIC")
+ENDIF(SUPPORT_FPIC)
+
 FILE(WRITE ${CMAKE_BINARY_DIR}/pthread_setpshared.c "
 #include <pthread.h>
 #include <stdlib.h>

cmake/CompilerWarnings.cmake

@@ -17,6 +17,9 @@ CHECK_C_COMPILER_FLAG(-Wnull-dereference SUPPORT_WNULL_DEREFERENCE)
 CHECK_C_COMPILER_FLAG(-Wduplicated-cond SUPPORT_WDUPLICATED_COND)
 # GCC 7 specific
 CHECK_C_COMPILER_FLAG(-Wimplicit-fallthrough SUPPORT_WIMPLICIT_FALLTHROUGH)
+# Special check for deprecated declarations, as since OpenSSL 3.0 they
+# just poison output for no good reason
+CHECK_C_COMPILER_FLAG(-Wdeprecated-declarations SUPPORT_WDEPRECATED_DECLARATIONS)
 
 IF(SUPPORT_WEXTRA)
     ADD_COMPILE_OPTIONS("-Wextra")
@@ -76,7 +79,6 @@ IF(SUPPORT_WMISSING_FORMAT_ATTRIBUTE)
     ADD_COMPILE_OPTIONS("-Wmissing-format-attribute")
 ENDIF(SUPPORT_WMISSING_FORMAT_ATTRIBUTE)
 
-CHECK_C_COMPILER_FLAG(-fPIC SUPPORT_FPIC)
-IF(SUPPORT_FPIC)
-    ADD_COMPILE_OPTIONS("-fPIC")
-ENDIF(SUPPORT_FPIC)
+IF(SUPPORT_WDEPRECATED_DECLARATIONS)
+    ADD_COMPILE_OPTIONS("-Wno-deprecated-declarations")
+ENDIF()