Clang attempts to guess file names based on the OS and distro (yes!),
but unfortunately, that doesn't work for us.

This patch makes it easy to insert libc's $libdir so that Clang passes the
correct absolute file name of crt1.o etc. to 'ld'.  It also disables all
the distro-specific stuff and removes the hard-coded FHS directory names
to make sure Clang also works on non-GuixSD systems.

This patch makes slight adjustments over "clang-libc-search-path.patch" for
changes in clang 3.8.

--- cfe-3.8.0.src/lib/Driver/ToolChains.cpp
+++ cfe-3.8.0.src/lib/Driver/ToolChains.cpp
@@ -3661,6 +3661,9 @@
                          GCCInstallation.getTriple().str() + "/bin")
                        .str());
 
+  // Comment out the distro-specific tweaks so that they don't bite when
+  // using Guix on a foreign distro.
+#if 0
   Distro Distro = DetectDistro(D, Arch);
 
   if (IsOpenSUSE(Distro) || IsUbuntu(Distro)) {
@@ -3702,6 +3705,7 @@
 
   if (IsOpenSUSE(Distro))
     ExtraOpts.push_back("--enable-new-dtags");
+#endif
 
   // The selection of paths to try here is designed to match the patterns which
   // the GCC driver itself uses, as this is part of the GCC-compatible driver.
@@ -3771,14 +3775,12 @@
     addPathIfExists(D, D.Dir + "/../" + OSLibDir, Paths);
   }
 
-  addPathIfExists(D, SysRoot + "/lib/" + MultiarchTriple, Paths);
-  addPathIfExists(D, SysRoot + "/lib/../" + OSLibDir, Paths);
-  addPathIfExists(D, SysRoot + "/usr/lib/" + MultiarchTriple, Paths);
-  addPathIfExists(D, SysRoot + "/usr/lib/../" + OSLibDir, Paths);
-
   // Try walking via the GCC triple path in case of biarch or multiarch GCC
   // installations with strange symlinks.
   if (GCCInstallation.isValid()) {
+    // The following code would end up adding things like
+    // "/usr/lib/x86_64-unknown-linux-gnu/../../lib64" to the search path.
+#if 0
     addPathIfExists(D,
                     SysRoot + "/usr/lib/" + GCCInstallation.getTriple().str() +
                         "/../../" + OSLibDir,
@@ -3791,6 +3793,7 @@
                              BiarchSibling.gccSuffix(),
                       Paths);
     }
+#endif
 
     // See comments above on the multilib variant for details of why this is
     // included even from outside the sysroot.
@@ -3815,8 +3818,9 @@
   if (StringRef(D.Dir).startswith(SysRoot))
     addPathIfExists(D, D.Dir + "/../lib", Paths);
 
-  addPathIfExists(D, SysRoot + "/lib", Paths);
-  addPathIfExists(D, SysRoot + "/usr/lib", Paths);
+  // Add libc's lib/ directory to the search path, so that crt1.o, crti.o,
+  // and friends can be found.
+  addPathIfExists(D, "@GLIBC_LIBDIR@", Paths);
 }
 
 bool Linux::HasNativeLLVMSupport() const { return true; }
Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2019-04-24 22:21:35 +0200'>2019-04-24</span></td><td><a href='/guix/commit/gnu/services/authentication.scm?id=9374cbd1fb29395a5e849e95e8a249e5f9f944c0'>services: fprintd: Provide polkit policy.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/authentication.scm (fprintd-service-type)[extensions]: Add
polkit-service-type.
</span></span></td><td>Danny Milosavljevic</td></tr>
<tr><td><span title='2019-04-21 10:40:19 +0200'>2019-04-21</span></td><td><a href='/guix/commit/gnu/services/authentication.scm?id=dc01978288318a8155e2e2657be9b278a754ebac'>services: fprintd: Use define-configuration.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/authentication.scm: Use define-configuration in fprintd.
</span></span></td><td>Danny Milosavljevic</td></tr>
<tr><td><span title='2019-04-17 08:51:11 +0200'>2019-04-17</span></td><td><a href='/guix/commit/gnu/services/authentication.scm?id=0682f084635cdc289aabafc4b2583639e00a28b3'>services: fprintd: Fix service.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/authentication.scm (&lt;fprintd-configuration&gt;)[ntp]: Rename to...
[fprintd]: ...this.
(fprintd-dbus-service): New procedure.
(fprintd-service-type): Use it.
[default-value]: Add value.
</span></span></td><td>Danny Milosavljevic</td></tr>
<tr><td><span title='2019-03-20 20:31:15 +0100'>2019-03-20</span></td><td><a href='/guix/commit/gnu/services/authentication.scm?id=c16423f143919916a5273761d7ed29bd49f14519'>services: Add nslcd-service-type.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/authentication.scm (nslcd-service-type, nslcd-configuration,
%nslcd-accounts): New variables.
(uglify-field-name, value-&gt;string, serialize-field, serialize-list,
ssl-option?, tls-reqcert-option?, deref-option?,
comma-separated-list-of-strings?, serialize-ignore-users-option, log-option?,
serialize-log-option, valid-map?, scope-option?, serialize-scope-option,
map-entry?, list-of-map-entries?, filter-entry?, list-of-filter-entries?,
serialize-filter-entry, serialize-list-of-filter-entries, serialize-map-entry,
serialize-list-of-map-entries, nslcd-config-file, nslcd-etc-service,
nslcd-shepherd-service, pam-ldap-pam-services, pam-ldap-pam-service,
generate-nslcd-documentation): New procedures.
* gnu/tests/ldap.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add it.
* doc/guix.texi (LDAP Services): Document it.
</span></span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2018-06-23 00:21:23 +0200'>2018-06-23</span></td><td><a href='/guix/commit/gnu/services/authentication.scm?id=812f6bd82dd584cc0551a687ec52315ae8ee4afb'>services: Fix "authentication" service name.</a><span class='msg-avail'>...<span class='msg-tooltip'>Follow-up to 7f93bbd5aadf0427190769fba8f478c29e37b4f4.

* gnu/services/authentication.scm: Fix module name.
</span></span></td><td>Danny Milosavljevic</td></tr>
<tr><td><span title='2018-06-23 00:14:27 +0200'>2018-06-23</span></td><td><a href='/guix/commit/gnu/services/authentication.scm?id=7f93bbd5aadf0427190769fba8f478c29e37b4f4'>services: Add fingerprint identification service.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/authentication.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add it.
* doc/guix.texi (Miscellaneous Services): Document it.
</span></span></td><td>Danny Milosavljevic</td></tr>