Add a no_prefix feature

There are some targets that we still force a prefix since they have
issues when their libc malloc is replaced in this way.

Closes #39

Cargo.toml

@@ -29,3 +29,4 @@ default = ["bg_thread"]
 profiling = ["jemalloc-sys/profiling"]
 debug = ["jemalloc-sys/debug"]
 bg_thread = ["jemalloc-sys/bg_thread"]
+no_prefix = ["jemalloc-sys/no_prefix"]

jemalloc-sys/Cargo.toml

@@ -28,3 +28,4 @@ default = ["bg_thread"]
 profiling = []
 debug = []
 bg_thread = []
+no_prefix = []

jemalloc-sys/build.rs

@@ -173,7 +173,21 @@ fn main() {
         cmd.arg("--with-malloc-conf=background_thread:false");
     }
 
-    cmd.arg("--with-jemalloc-prefix=_rjem_");
+    let mut use_prefix = !env::var_os("CARGO_FEATURE_NO_PREFIX").is_some();
+    if !use_prefix &&
+        (target.contains("android")
+            || target.contains("dragonfly")
+            || target.contains("musl")
+            || target.contains("darwin"))
+    {
+        println!("ignoring no_prefix feature on unsupported platform");
+        use_prefix = true;
+    }
+
+    if use_prefix {
+        cmd.arg("--with-jemalloc-prefix=_rjem_");
+        println!("cargo:rustc-cfg=prefixed");
+    }
 
     if env::var_os("CARGO_FEATURE_DEBUG").is_some() {
         println!("CARGO_FEATURE_DEBUG set");
@@ -181,7 +195,7 @@ fn main() {
     }
 
     if env::var_os("CARGO_FEATURE_PROFILING").is_some() {
-        println!("CARGO_FEATURE_PROFILING set set");
+        println!("CARGO_FEATURE_PROFILING set");
         cmd.arg("--enable-prof");
     }
     cmd.arg(format!("--host={}", gnu_target(&target)));

jemalloc-sys/src/lib.rs

@@ -18,48 +18,48 @@ pub const MALLOCX_ZERO: c_int = 0x40;
 
 extern "C" {
     // Standard API
-    #[link_name = "_rjem_malloc"]
+    #[cfg_attr(prefixed, link_name = "_rjem_malloc")]
     pub fn malloc(size: size_t) -> *mut c_void;
-    #[link_name = "_rjem_calloc"]
+    #[cfg_attr(prefixed, link_name = "_rjem_calloc")]
     pub fn calloc(number: size_t, size: size_t) -> *mut c_void;
-    #[link_name = "_rjem_posix_memalign"]
+    #[cfg_attr(prefixed, link_name = "_rjem_posix_memalign")]
     pub fn posix_memalign(ptr: *mut *mut c_void, alignment: size_t, size: size_t) -> c_int;
-    #[link_name = "_rjem_aligned_alloc"]
+    #[cfg_attr(prefixed, link_name = "_rjem_aligned_alloc")]
     pub fn aligned_alloc(alignment: size_t, size: size_t) -> *mut c_void;
-    #[link_name = "_rjem_realloc"]
+    #[cfg_attr(prefixed, link_name = "_rjem_realloc")]
     pub fn realloc(ptr: *mut c_void, size: size_t) -> *mut c_void;
-    #[link_name = "_rjem_free"]
+    #[cfg_attr(prefixed, link_name = "_rjem_free")]
     pub fn free(ptr: *mut c_void);
 
     // Non-standard API
-    #[link_name = "_rjem_mallocx"]
+    #[cfg_attr(prefixed, link_name = "_rjem_mallocx")]
     pub fn mallocx(size: size_t, flags: c_int) -> *mut c_void;
-    #[link_name = "_rjem_rallocx"]
+    #[cfg_attr(prefixed, link_name = "_rjem_rallocx")]
     pub fn rallocx(ptr: *mut c_void, size: size_t, flags: c_int) -> *mut c_void;
-    #[link_name = "_rjem_xallocx"]
+    #[cfg_attr(prefixed, link_name = "_rjem_xallocx")]
     pub fn xallocx(ptr: *mut c_void, size: size_t, extra: size_t, flags: c_int) -> size_t;
-    #[link_name = "_rjem_sallocx"]
+    #[cfg_attr(prefixed, link_name = "_rjem_sallocx")]
     pub fn sallocx(ptr: *const c_void, flags: c_int) -> size_t;
-    #[link_name = "_rjem_dallocx"]
+    #[cfg_attr(prefixed, link_name = "_rjem_dallocx")]
     pub fn dallocx(ptr: *mut c_void, flags: c_int);
-    #[link_name = "_rjem_sdallocx"]
+    #[cfg_attr(prefixed, link_name = "_rjem_sdallocx")]
     pub fn sdallocx(ptr: *mut c_void, size: size_t, flags: c_int);
-    #[link_name = "_rjem_nallocx"]
+    #[cfg_attr(prefixed, link_name = "_rjem_nallocx")]
     pub fn nallocx(size: size_t, flags: c_int) -> size_t;
-    #[link_name = "_rjem_malloc_usable_size"]
+    #[cfg_attr(prefixed, link_name = "_rjem_malloc_usable_size")]
     pub fn malloc_usable_size(ptr: *const c_void) -> size_t;
 
     // mallctl
-    #[link_name = "_rjem_mallctl"]
+    #[cfg_attr(prefixed, link_name = "_rjem_mallctl")]
     pub fn mallctl(name: *const c_char,
                    oldp: *mut c_void,
                    oldpenp: *mut size_t,
                    newp: *mut c_void,
                    newlen: size_t)
                    -> c_int;
-    #[link_name = "_rjem_mallctlnametomib"]
+    #[cfg_attr(prefixed, link_name = "_rjem_mallctlnametomib")]
     pub fn mallctlnametomib(name: *const c_char, mibp: *mut size_t, miblenp: *mut size_t) -> c_int;
-    #[link_name = "_rjem_mallctlbymib"]
+    #[cfg_attr(prefixed, link_name = "_rjem_mallctlbymib")]
     pub fn mallctlbymib(mib: *const size_t,
                         miblen: size_t,
                         oldp: *mut c_void,
@@ -69,7 +69,7 @@ extern "C" {
                         -> c_int;
 
     // stats
-    #[link_name = "_rjem_malloc_stats_print"]
+    #[cfg_attr(prefixed, link_name = "_rjem_malloc_stats_print")]
     pub fn malloc_stats_print(write_cb: extern "C" fn(*mut c_void, *const c_char),
                               cbopaque: *mut c_void,
                               opts: *const c_char);