diff --git a/spot/misc/common.hh b/spot/misc/common.hh
index 4d3a12766..a7fb1e076 100644
--- a/spot/misc/common.hh
+++ b/spot/misc/common.hh
@@ -67,7 +67,7 @@
 // Else use SPOT_ASSERT so the assert() are removed from user's
 // builds.
 #define spot_assert__ assert
-#if defined(SPOT_BUILD) or defined(SPOT_DEBUG)
+#if defined(SPOT_BUILD) || defined(SPOT_DEBUG)
   #define SPOT_ASSERT(x) spot_assert__(x)
 #else
    // Do not replace by SPOT_ASSUME(x), as x can have some costly
diff --git a/spot/tl/formula.hh b/spot/tl/formula.hh
index 3ab6dd100..4f56c38bc 100644
--- a/spot/tl/formula.hh
+++ b/spot/tl/formula.hh
@@ -59,7 +59,7 @@
 // The strong_X operator was introduced in Spot 2.8.2 to fix an issue
 // with from_ltlf().  As adding a new operator is a backward
 // incompatibility, causing new warnings from the compiler.
-#if defined(SPOT_BUILD) or defined(SPOT_USES_STRONG_X)
+#if defined(SPOT_BUILD) || defined(SPOT_USES_STRONG_X)
 // Use #if SPOT_HAS_STRONG_X in code that need to be backward
 // compatible with older Spot versions.
 #  define SPOT_HAS_STRONG_X 1