diff --git a/configfiles/mock.cfg.template b/configfiles/mock.cfg.template
index 84119a5c..abaa0ec8 100644
--- a/configfiles/mock.cfg.template
+++ b/configfiles/mock.cfg.template
@@ -10,6 +10,7 @@ config_opts['cleanup_on_success'] = False
 
 # Make sure static libraries are deterministic
 config_opts['macros']['__brp_strip_static_archive'] = '/usr/lib/rpm/brp-strip-static-archive "%{__strip} -D"'
+config_opts['macros']['_preprocessor_defines'] = '-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -D_FILE_OFFSET_BITS=64'
 
 # Autogenerated common configuration
 {{- range $key,$val := .DefaultCommonCfg}}
diff --git a/impl/testData/expected-mock.cfg b/impl/testData/expected-mock.cfg
index d0b3d0dd..51dded75 100644
--- a/impl/testData/expected-mock.cfg
+++ b/impl/testData/expected-mock.cfg
@@ -10,6 +10,7 @@ config_opts['cleanup_on_success'] = False
 
 # Make sure static libraries are deterministic
 config_opts['macros']['__brp_strip_static_archive'] = '/usr/lib/rpm/brp-strip-static-archive "%{__strip} -D"'
+config_opts['macros']['_preprocessor_defines'] = '-Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -D_FILE_OFFSET_BITS=64'
 
 # Autogenerated common configuration
 config_opts['resultdir'] = "{{.TestWorkingDir}}/work/pkg1/mock-x86_64/mock-results"