diff --git a/configure.ac b/configure.ac
index db526c47e..c7fb39945 100644
--- a/configure.ac
+++ b/configure.ac
@@ -749,6 +749,25 @@ AM_COND_IF([DEBUG],
 	])
 ])
 
+AM_COND_IF([BUILD_PCH],
+[
+	AM_COND_IF([GCC],
+	[
+		RB_VAR_PREPEND([CXXFLAGS], ["-fpch-deps"])
+	])
+
+	AM_COND_IF([CLANG],
+	[
+		RB_VAR_PREPEND([CPPFLAGS], ["-fpch-preprocess"])
+		RB_VAR_PREPEND([CXXFLAGS], ["-Xclang -verify-pch"])
+	])
+
+	AM_COND_IF([CLANG10],
+	[
+		RB_VAR_PREPEND([CXXFLAGS], ["-fpch-validate-input-files-content"])
+	])
+])
+
 dnl
 dnl Runtime intrumentation
 dnl
diff --git a/include/ircd/Makefile.am b/include/ircd/Makefile.am
index 4fe2cd1fb..1540bd85f 100644
--- a/include/ircd/Makefile.am
+++ b/include/ircd/Makefile.am
@@ -6,18 +6,6 @@ AM_CPPFLAGS += -I$(top_srcdir)/include
 AM_CXXFLAGS =#
 AM_CXXFLAGS += -x c++-header
 
-if GCC
-AM_CXXFLAGS += -fpch-deps
-endif
-
-if CLANG
-AM_CPPFLAGS += -fpch-preprocess
-endif
-
-if CLANG10
-AM_CXXFLAGS += -fpch-validate-input-files-content
-endif
-
 if CLANG11
 AM_CXXFLAGS += -fpch-instantiate-templates
 endif