diff --git a/src/common.h b/src/common.h
index 46953359f..4ea4637df 100644
--- a/src/common.h
+++ b/src/common.h
@@ -4,6 +4,7 @@
 #include "config.h"  // IWYU pragma: keep
 
 #include <errno.h>
+#include <limits.h>
 #include <pthread.h>
 #include <stdarg.h>  // IWYU pragma: keep
 #include <stddef.h>
@@ -89,6 +90,17 @@ typedef std::vector<wcstring> wcstring_list_t;
 #define INPUT_COMMON_BASE (wchar_t)0xF700
 #define INPUT_COMMON_END (INPUT_COMMON_BASE + 64)
 
+// NAME_MAX is not defined on Solaris
+#if !defined(NAME_MAX)
+#include <sys/param.h>
+#if defined(MAXNAMELEN)
+// MAXNAMELEN is defined on Linux, BSD, and Solaris among others
+#define NAME_MAX MAXNAMELEN
+#else
+static_assert(false, "Neither NAME_MAX nor MAXNAMELEN is defined!");
+#endif
+#endif
+
 enum escape_string_style_t { STRING_STYLE_SCRIPT, STRING_STYLE_URL, STRING_STYLE_VAR };
 
 // Flags for unescape_string functions.
diff --git a/src/env_universal_common.cpp b/src/env_universal_common.cpp
index eac8b1e10..86ad085bd 100644
--- a/src/env_universal_common.cpp
+++ b/src/env_universal_common.cpp
@@ -55,13 +55,6 @@
 #include <bsd/ifaddrs.h>
 #endif  // Haiku
 
-// NAME_MAX is not defined on Solaris and suggests the use of pathconf()
-// There is no obvious sensible pathconf() for shared memory and _XPG_NAME_MAX
-// seems a reasonable choice.
-#if !defined(NAME_MAX) && defined(_XOPEN_NAME_MAX)
-#define NAME_MAX _XOPEN_NAME_MAX
-#endif
-
 /// The set command.
 #define SET_STR L"SET"
 
diff --git a/src/wutil.cpp b/src/wutil.cpp
index d777555bf..ab5de1d76 100644
--- a/src/wutil.cpp
+++ b/src/wutil.cpp
@@ -92,7 +92,7 @@ bool wreaddir(DIR *dir, wcstring &out_name) {
     // long when it should be at least NAME_MAX + 1.
     union {
         struct dirent d;
-        char c[offsetof(struct dirent, d_name) + NAME_MAX + 1]; /* NAME_MAX is POSIX. */
+        char c[offsetof(struct dirent, d_name) + NAME_MAX + 1];
     } d_u;
     struct dirent *result = NULL;