diff --git a/hledger-lib/hledger-lib.cabal b/hledger-lib/hledger-lib.cabal
index 4123f66ff..56a5964da 100644
--- a/hledger-lib/hledger-lib.cabal
+++ b/hledger-lib/hledger-lib.cabal
@@ -83,6 +83,9 @@ library
     , HUnit
     , parsec
     , semigroups
+  if impl(ghc <7.6)
+    build-depends:
+        ghc-prim
   if flag(oldtime)
     build-depends:
         time <1.5
@@ -170,6 +173,9 @@ test-suite doctests
     , HUnit
     , doctest >=0.8
     , Glob >=0.7
+  if impl(ghc <7.6)
+    build-depends:
+        ghc-prim
   default-language: Haskell2010
 
 test-suite hunittests
@@ -208,6 +214,9 @@ test-suite hunittests
     , hledger-lib
     , test-framework
     , test-framework-hunit
+  if impl(ghc <7.6)
+    build-depends:
+        ghc-prim
   if flag(oldtime)
     build-depends:
         time <1.5
diff --git a/hledger-lib/package.yaml b/hledger-lib/package.yaml
index 4845f91e1..1448aebc5 100644
--- a/hledger-lib/package.yaml
+++ b/hledger-lib/package.yaml
@@ -118,6 +118,9 @@ library:
   - parsec
   - semigroups
   when:
+  - condition: impl(ghc <7.6)
+    dependencies:
+    - ghc-prim
   - condition: flag(oldtime)
     then:
       dependencies:
@@ -133,6 +136,10 @@ tests:
     dependencies:
     - doctest >=0.8
     - Glob >=0.7
+    when:
+    - condition: impl(ghc <7.6)
+      dependencies:
+      - ghc-prim
   hunittests:
     main: hunittests.hs
     source-dirs: tests
@@ -141,6 +148,9 @@ tests:
     - test-framework
     - test-framework-hunit
     when:
+    - condition: impl(ghc <7.6)
+      dependencies:
+      - ghc-prim
     - condition: flag(oldtime)
       then:
         dependencies:
diff --git a/hledger-web/hledger-web.cabal b/hledger-web/hledger-web.cabal
index 8b40910a5..ffd6591ef 100644
--- a/hledger-web/hledger-web.cabal
+++ b/hledger-web/hledger-web.cabal
@@ -170,6 +170,9 @@ library
     else
         build-depends:
               time >=1.5
+    if impl(ghc <7.6)
+        build-depends:
+              ghc-prim
     exposed-modules:
           Application
           Foundation
@@ -247,6 +250,9 @@ executable hledger-web
     else
         build-depends:
               time >=1.5
+    if impl(ghc <7.6)
+        build-depends:
+              ghc-prim
     default-language: Haskell2010
 
 test-suite test
@@ -302,4 +308,7 @@ test-suite test
     else
         build-depends:
               time >=1.5
+    if impl(ghc <7.6)
+        build-depends:
+              ghc-prim
     default-language: Haskell2010
diff --git a/hledger-web/package.yaml b/hledger-web/package.yaml
index d80223918..5496d8723 100644
--- a/hledger-web/package.yaml
+++ b/hledger-web/package.yaml
@@ -132,6 +132,9 @@ library:
     else:
       dependencies:
       - time >=1.5
+  - condition: impl(ghc <7.6)
+    dependencies:
+    - ghc-prim
 executables:
   hledger-web:
     main: main.hs
@@ -157,6 +160,9 @@ executables:
       else:
         dependencies:
         - time >=1.5
+    - condition: impl(ghc <7.6)
+      dependencies:
+      - ghc-prim
 tests:
   test:
     main: main.hs
@@ -175,5 +181,8 @@ tests:
       else:
         dependencies:
         - time >=1.5
+    - condition: impl(ghc <7.6)
+      dependencies:
+      - ghc-prim
 stability: stable
 tested-with: GHC==7.6.3, GHC==7.8.4, GHC==7.10.3, GHC==8.0
diff --git a/hledger/hledger.cabal b/hledger/hledger.cabal
index da59bae7d..894682caf 100644
--- a/hledger/hledger.cabal
+++ b/hledger/hledger.cabal
@@ -111,6 +111,9 @@ library
     , text >=0.11
     , utf8-string >=0.3.5 && <1.1
     , wizards ==1.0.*
+  if impl(ghc <7.6)
+    build-depends:
+        ghc-prim
   if impl(ghc >=7.10)
     build-depends:
         shakespeare >=2.0.2.2 && <2.1
@@ -192,6 +195,9 @@ executable hledger
     , wizards ==1.0.*
   if flag(threaded)
     ghc-options: -threaded
+  if impl(ghc <7.6)
+    build-depends:
+        ghc-prim
   if impl(ghc >=7.10)
     build-depends:
         shakespeare >=2.0.2.2 && <2.1
@@ -250,6 +256,9 @@ test-suite test
     , wizards ==1.0.*
     , test-framework
     , test-framework-hunit
+  if impl(ghc <7.6)
+    build-depends:
+        ghc-prim
   if impl(ghc >=7.10)
     build-depends:
         shakespeare >=2.0.2.2 && <2.1
diff --git a/hledger/package.yaml b/hledger/package.yaml
index 63136d872..133bbea43 100644
--- a/hledger/package.yaml
+++ b/hledger/package.yaml
@@ -125,6 +125,9 @@ library:
   - utf8-string >=0.3.5 && <1.1
   - wizards ==1.0.*
   when:
+  - condition: impl(ghc <7.6)
+    dependencies:
+    - ghc-prim
   - condition: impl(ghc >=7.10)
     then:
       dependencies:
@@ -173,6 +176,9 @@ executables:
     when:
     - condition: flag(threaded)
       ghc-options: -threaded
+    - condition: impl(ghc <7.6)
+      dependencies:
+      - ghc-prim
     - condition: impl(ghc >=7.10)
       then:
         dependencies:
@@ -221,6 +227,9 @@ tests:
     - test-framework
     - test-framework-hunit
     when:
+    - condition: impl(ghc <7.6)
+      dependencies:
+      - ghc-prim
     - condition: impl(ghc >=7.10)
       then:
         dependencies: