macro: Introduce ABS() macro and use it in header files

abs() requires including the entirety of stdlib.h just for a single
trivial function. Let's introduce the ABS() macro and use it in header
files instead so we can get rid of stdlib.h transitive includes in header
files in a later commit.

src/basic/errno-list.h

@@ -2,9 +2,10 @@
 #pragma once
 
 #include <stdbool.h>
-#include <stdlib.h>
 #include <string.h>
 
+#include "macro.h"
+
 /*
  * MAX_ERRNO is defined as 4095 in linux/err.h
  * We use the same value here.
@@ -16,7 +17,7 @@ static inline const char* errno_to_name(int id) {
         if (id == 0) /* To stay in line with our own impl */
                 return NULL;
 
-        return strerrorname_np(abs(id));
+        return strerrorname_np(ABS(id));
 }
 #else
 const char* errno_to_name(int id);

src/basic/errno-util.h

@@ -2,7 +2,6 @@
 #pragma once
 
 #include <inttypes.h>
-#include <stdlib.h>
 #include <string.h>
 
 #include "assert-util.h"
@@ -16,7 +15,7 @@
  * https://stackoverflow.com/questions/34880638/compound-literal-lifetime-and-if-blocks
  *
  * Note that we use the GNU variant of strerror_r() here. */
-#define STRERROR(errnum) strerror_r(abs(errnum), (char[ERRNO_BUF_LEN]){}, ERRNO_BUF_LEN)
+#define STRERROR(errnum) strerror_r(ABS(errnum), (char[ERRNO_BUF_LEN]){}, ERRNO_BUF_LEN)
 
 /* A helper to print an error message or message for functions that return 0 on EOF.
  * Note that we can't use ({ … }) to define a temporary variable, so errnum is
@@ -41,7 +40,7 @@ static inline void _reset_errno_(int *saved_errno) {
 
 #define LOCAL_ERRNO(value)                      \
         PROTECT_ERRNO;                          \
-        errno = abs(value)
+        errno = ABS(value)
 
 static inline int negative_errno(void) {
         /* This helper should be used to shut up gcc if you know 'errno' is
@@ -93,15 +92,14 @@ static inline int errno_or_else(int fallback) {
         if (errno > 0)
                 return -errno;
 
-        return -abs(fallback);
+        return -ABS(fallback);
 }
 
-/* abs(3) says: Trying to take the absolute value of the most negative integer is not defined. */
 #define _DEFINE_ABS_WRAPPER(name)                         \
         static inline bool ERRNO_IS_##name(intmax_t r) {  \
                 if (r == INTMAX_MIN)                      \
                         return false;                     \
-                return ERRNO_IS_NEG_##name(-imaxabs(r));  \
+                return ERRNO_IS_NEG_##name(-ABS(r));      \
         }
 
 assert_cc(INT_MAX <= INTMAX_MAX);

src/basic/log.h

@@ -33,9 +33,9 @@ typedef enum LogTarget{
 #define LOG_NULL (LOG_EMERG - 1)
 assert_cc(LOG_NULL == -1);
 
-#define SYNTHETIC_ERRNO(num)                (abs(num) | (1 << 30))
+#define SYNTHETIC_ERRNO(num)                (ABS(num) | (1 << 30))
 #define IS_SYNTHETIC_ERRNO(val)             (((val) >> 30) == 1)
-#define ERRNO_VALUE(val)                    (abs(val) & ~(1 << 30))
+#define ERRNO_VALUE(val)                    (ABS(val) & ~(1 << 30))
 
 /* The callback function to be invoked when syntax warnings are seen
  * in the unit files. */

src/basic/macro.h

@@ -105,7 +105,7 @@ static inline size_t GREEDY_ALLOC_ROUND_UP(size_t l) {
 
 #define return_with_errno(r, err)                     \
         do {                                          \
-                errno = abs(err);                     \
+                errno = ABS(err);                     \
                 return r;                             \
         } while (false)
 

src/cryptsetup/cryptsetup-tokens/cryptsetup-token-util.h

@@ -6,6 +6,8 @@
 #include <stdbool.h>
 #include <stddef.h>
 
+#include "macro.h"
+
 /* crypt_dump() internal indentation magic */
 #define CRYPT_DUMP_LINE_SEP "\n\t            "
 
@@ -15,7 +17,7 @@
 #define crypt_log(cd, ...)         crypt_logf(cd, CRYPT_LOG_NORMAL,  __VA_ARGS__)
 
 #define crypt_log_full_errno(cd, e, lvl, ...) ({ \
-        int _e = abs(e), _s = errno; \
+        int _e = ABS(e), _s = errno; \
         errno = _e; \
         crypt_logf(cd, lvl, __VA_ARGS__); \
         errno = _s; \

src/fundamental/macro-fundamental.h

@@ -176,6 +176,13 @@
                 UNIQ_T(A, aq) > UNIQ_T(B, bq) ? UNIQ_T(A, aq) : UNIQ_T(B, bq); \
         })
 
+#define ABS(a) __ABS(UNIQ, (a))
+#define __ABS(aq, a)                                    \
+({                                                      \
+        const typeof(a) UNIQ_T(A, aq) = (a);            \
+        UNIQ_T(A, aq) < 0 ? -UNIQ_T(A, aq) : UNIQ_T(A, aq); \
+})
+
 #define IS_UNSIGNED_INTEGER_TYPE(type) \
         (__builtin_types_compatible_p(typeof(type), unsigned char) ||   \
          __builtin_types_compatible_p(typeof(type), unsigned short) ||  \

src/libsystemd/sd-journal/journal-internal.h

@@ -149,7 +149,7 @@ int journal_add_matchf(sd_journal *j, const char *format, ...) _printf_(2, 3);
 /* All errors that we might encounter while extracting a field that are not real errors,
  * but only mean that the field is too large or we don't support the compression. */
 static inline bool JOURNAL_ERRNO_IS_UNAVAILABLE_FIELD(int r) {
-        return IN_SET(abs(r),
+        return IN_SET(ABS(r),
                       ENOBUFS,          /* Field or decompressed field too large */
                       E2BIG,            /* Field too large for pointer width */
                       EPROTONOSUPPORT); /* Unsupported compression */

src/shared/plymouth-util.h

@@ -10,5 +10,5 @@ int plymouth_send_raw(const void *raw, size_t size, int flags);
 int plymouth_send_msg(const char *text, bool pause_spinner);
 
 static inline bool ERRNO_IS_NO_PLYMOUTH(int r) {
-        return IN_SET(abs(r), EAGAIN, ENOENT) || ERRNO_IS_DISCONNECT(r);
+        return IN_SET(ABS(r), EAGAIN, ENOENT) || ERRNO_IS_DISCONNECT(r);
 }

src/shared/tests.h

@@ -40,7 +40,7 @@ static inline void log_set_assert_return_is_criticalp(bool *p) {
 #define ASSERT_RETURN_EXPECTED_SE(expr) ASSERT_RETURN_EXPECTED(assert_se(expr));
 
 static inline bool manager_errno_skip_test(int r) {
-        return IN_SET(abs(r),
+        return IN_SET(ABS(r),
                       EPERM,
                       EACCES,
                       EADDRINUSE,