diff --git a/cpp/libc.cc b/cpp/libc.cc
index c4d0f98705..67ed8f6935 100644
--- a/cpp/libc.cc
+++ b/cpp/libc.cc
@@ -6,7 +6,6 @@
 #include <fnmatch.h>
 #include <glob.h>
 #include <locale.h>
-#include <regex.h>
 #include <stdlib.h>  // getenv()
 #include <sys/ioctl.h>
 #include <unistd.h>  // gethostname()
@@ -17,110 +16,92 @@
 
 namespace libc {
 
-class RegexCache {
- public:
-  static const int kDefaultSize = 100;
-
-  struct CacheEntry {
-    CacheEntry() = delete;
-    CacheEntry(const CacheEntry&) = delete;
-
-    CacheEntry(BigStr* pat, int cflags) : pat_() {
-      int status = ::regcomp(&compiled_, pat->data_, cflags);
-      if (status != 0) {
-        char error_desc[50];
-        regerror(status, &compiled_, error_desc, 50);
+RegexCache::CacheEntry::CacheEntry(BigStr* pat, int cflags) : pat_() {
+  int status = ::regcomp(&compiled_, pat->data_, cflags);
+  if (status != 0) {
+    char error_desc[50];
+    regerror(status, &compiled_, error_desc, 50);
 
-        char error_message[80];
-        snprintf(error_message, 80, "Invalid regex %s (%s)", pat->data_,
-                 error_desc);
+    char error_message[80];
+    snprintf(error_message, 80, "Invalid regex %s (%s)", pat->data_,
+             error_desc);
 
-        throw Alloc<ValueError>(StrFromC(error_message));
-      }
+    throw Alloc<ValueError>(StrFromC(error_message));
+  }
 
-      pat_ = static_cast<char*>(malloc(len(pat) + 1));
-      memcpy(pat_, pat->data_, len(pat) + 1);
-      pat_hash_ = hash(pat);
-    }
+  pat_ = static_cast<char*>(malloc(len(pat) + 1));
+  memcpy(pat_, pat->data_, len(pat) + 1);
+  pat_hash_ = hash(pat);
+}
 
-    ~CacheEntry() {
-      DCHECK(pat_ != nullptr);
-      free(pat_);
-      regfree(&compiled_);
-    }
+RegexCache::CacheEntry::~CacheEntry() {
+  DCHECK(pat_ != nullptr);
+  free(pat_);
+  regfree(&compiled_);
+}
 
-    char* pat_;
-    int pat_hash_;
-    regex_t compiled_;
-  };
-
-  RegexCache(int capacity) : capacity_(capacity), access_list_() {
-    // Override if env var is set.
-    char* e = getenv("OILS_REGEX_CACHE_SIZE");
-    if (e) {
-      int result;
-      if (StringToInteger(e, strlen(e), 10, &result)) {
-        capacity_ = result;
-      }
+RegexCache::RegexCache(int capacity) : capacity_(capacity), access_list_() {
+  // Override if env var is set.
+  char* e = getenv("OILS_REGEX_CACHE_SIZE");
+  if (e) {
+    int result;
+    if (StringToInteger(e, strlen(e), 10, &result)) {
+      capacity_ = result;
     }
   }
+}
 
-  ~RegexCache() {
-    for (auto& it : access_list_) {
-      delete it;
-    }
+RegexCache::~RegexCache() {
+  for (auto& it : access_list_) {
+    delete it;
   }
+}
 
-  regex_t* regcomp(BigStr* pat, int cflags) {
-    CacheEntry* entry = TakeEntry(pat);
-    if (entry == nullptr) {
-      // Dealing with a new entry. Make space and compile.
-      MaybeEvict();
-      entry = new CacheEntry(pat, cflags);
-    }
-
-    SetMostRecent(entry);
-
-    return &entry->compiled_;
+regex_t* RegexCache::regcomp(BigStr* pat, int cflags) {
+  RegexCache::CacheEntry* entry = TakeEntry(pat);
+  if (entry == nullptr) {
+    // Dealing with a new entry. Make space and compile.
+    MaybeEvict();
+    entry = new RegexCache::CacheEntry(pat, cflags);
   }
 
- private:
-  CacheEntry* TakeEntry(BigStr* pat) {
-    auto it = std::find_if(access_list_.begin(), access_list_.end(),
-                           [pat](CacheEntry* entry) {
-                             return hash(pat) == entry->pat_hash_ &&
-                                    strcmp(pat->data_, entry->pat_) == 0;
-                           });
-    if (it == access_list_.end()) {
-      return nullptr;
-    }
+  SetMostRecent(entry);
+
+  return &entry->compiled_;
+}
 
-    CacheEntry* ret = *it;
-    access_list_.erase(it);
-    return ret;
+RegexCache::CacheEntry* RegexCache::TakeEntry(BigStr* pat) {
+  auto it = std::find_if(access_list_.begin(), access_list_.end(),
+                         [pat](RegexCache::CacheEntry* entry) {
+                           return hash(pat) == entry->pat_hash_ &&
+                                  strcmp(pat->data_, entry->pat_) == 0;
+                         });
+  if (it == access_list_.end()) {
+    return nullptr;
   }
 
-  void MaybeEvict() {
-    if (access_list_.size() < capacity_) {
-      return;
-    }
+  RegexCache::CacheEntry* ret = *it;
+  access_list_.erase(it);
+  return ret;
+}
 
-    // Evict the least recently used entry.
-    if (access_list_.size()) {
-      delete *access_list_.begin();
-      access_list_.erase(access_list_.begin());
-    }
+void RegexCache::MaybeEvict() {
+  if (access_list_.size() < capacity_) {
+    return;
   }
 
-  void SetMostRecent(CacheEntry* entry) {
-    access_list_.push_back(entry);
+  // Evict the least recently used entry.
+  if (access_list_.size()) {
+    delete *access_list_.begin();
+    access_list_.erase(access_list_.begin());
   }
+}
 
-  size_t capacity_;
-  std::vector<CacheEntry*> access_list_;
-};
+void RegexCache::SetMostRecent(RegexCache::CacheEntry* entry) {
+  access_list_.push_back(entry);
+}
 
-static RegexCache gRegexCache(RegexCache::kDefaultSize);
+RegexCache gRegexCache(RegexCache::kDefaultSize);
 
 BigStr* gethostname() {
   // Note: Fixed issue #1656 - OS X and FreeBSD don't have HOST_NAME_MAX
diff --git a/cpp/libc.h b/cpp/libc.h
index b209125530..7753830e5d 100644
--- a/cpp/libc.h
+++ b/cpp/libc.h
@@ -3,6 +3,7 @@
 #ifndef LIBC_H
 #define LIBC_H
 
+#include <regex.h>
 #include <stdlib.h>
 
 #include "mycpp/runtime.h"
@@ -33,6 +34,38 @@ List<int>* regex_search(BigStr* pattern, int cflags, BigStr* str, int eflags,
 int wcswidth(BigStr* str);
 int get_terminal_width();
 
+class RegexCache {
+ public:
+  static const int kDefaultSize = 100;
+
+  struct CacheEntry {
+    CacheEntry() = delete;
+    CacheEntry(const CacheEntry&) = delete;
+
+    CacheEntry(BigStr* pat, int cflags);
+    ~CacheEntry();
+
+    char* pat_;
+    int pat_hash_;
+    regex_t compiled_;
+  };
+
+  RegexCache(int capacity);
+  ~RegexCache();
+
+  regex_t* regcomp(BigStr* pat, int cflags);
+
+ private:
+  CacheEntry* TakeEntry(BigStr* pat);
+  void MaybeEvict();
+  void SetMostRecent(CacheEntry* entry);
+
+  size_t capacity_;
+  std::vector<CacheEntry*> access_list_;
+};
+
+extern RegexCache gRegexCache;
+
 }  // namespace libc
 
 #endif  // LIBC_H
diff --git a/cpp/libc_test.cc b/cpp/libc_test.cc
index 0d65d24301..fee45fbeed 100644
--- a/cpp/libc_test.cc
+++ b/cpp/libc_test.cc
@@ -146,13 +146,13 @@ TEST for_test_coverage() {
 }
 
 void FindAll(const char* p, const char* s) {
-  regex_t pat;
+  regex_t* pat;
 
   int cflags = REG_EXTENDED;
-  if (regcomp(&pat, p, cflags) != 0) {
+  if ((pat = libc::gRegexCache.regcomp(StrFromC(p), cflags)) == nullptr) {
     FAIL();
   }
-  int outlen = pat.re_nsub + 1;  // number of captures
+  int outlen = pat->re_nsub + 1;  // number of captures
 
   // TODO: Could statically allocate 99, and assert that re_nsub is less than
   // 99.  Would speed up loops.
@@ -164,7 +164,7 @@ void FindAll(const char* p, const char* s) {
   while (true) {
     // Necessary so ^ doesn't match in the middle!
     int eflags = cur_pos == 0 ? 0 : REG_NOTBOL;
-    bool match = regexec(&pat, s + cur_pos, outlen, pmatch, eflags) == 0;
+    bool match = regexec(pat, s + cur_pos, outlen, pmatch, eflags) == 0;
 
     if (!match) {
       break;
@@ -186,7 +186,6 @@ void FindAll(const char* p, const char* s) {
   }
 
   free(pmatch);
-  regfree(&pat);
 }
 
 // adjacent matches